Methods of identifying multiple epitopes in cells

ABSTRACT

The invention provides methods, compositions, kits and devices for the detection of target molecules. In some embodiments, the invention allows for multiplexed target molecule detection.

CROSS-REFERENCE

This application is a continuation of U.S. application Ser. No.17/951,013, filed on Sep. 22, 2022, which is a continuation of U.S.application Ser. No. 17/870,697, filed on Jul. 21, 2022, which is acontinuation of U.S. application Ser. No. 16/795,203, filed on Feb. 19,2020, which is a continuation of U.S. application Ser. No. 16/147,250,filed on Sep. 28, 2018, now issued as U.S. Pat. No. 10,982,256, which isa continuation of U.S. application Ser. No. 13/981,711, filed on Apr.15, 2016, now issued as U.S. Pat. No. 10,144,950, which is a § 371national phase of International Application No. PCT/US2012/023411, filedon Jan. 31, 2012, which claims priority to U.S. application Ser. No.61/437,854 filed on Jan. 31, 2011 and 61/444,067 filed on Feb. 17, 2011,all of which applications are incorporated herein by reference in theirentireties.

BACKGROUND OF THE INVENTION

Although all cells in the human body contain the same genetic material,the same genes are not active in all of those cells. Alterations in geneexpression patterns can have profound effects on biological functions.Furthermore, understanding the dynamics and the regulation of geneproducts (proteins), their variants, and interacting partners isessential in understanding, for example, the mechanisms behindgenetic/and environmentally induced disorders or the influences of drugmediated therapies. This understanding can potentially become theunderlying foundation for further clinical and diagnostic analyses.Therefore, identifying and quantifying the expression and regulation ofgenes and/or their products in cells can aid the discovery of newtherapeutic and diagnostic targets.

Critical to these studies is the ability to qualitatively determine geneexpression and specific variants of whole proteins (e.g., splicevariants, point mutations, post-translationally modified versions, andenvironmentally/therapeutically-induced modifications) and the abilityto view their quantitative modulation. Moreover, it is becomingincreasing important to perform these analyses from not just one, butmultiple target molecules in a cell. The methods available to date stillrequire significant amounts of biological samples or will not providecell specific information. Additionally, there are limited methods ofmultiplexed protein measurement technologies due to the additionalchallenges inherent in protein samples.

Thus, there exists a need for accurate and sensitive detection,identification and quantification of target molecules in every cell of acomplex cell population and to retain cell specific informationregarding that target molecule.

SUMMARY OF THE INVENTION

The invention relates generally to the field of detection,identification, and quantification of target molecules in a sample. Thepresent invention relates in part to the detection, identification, andquantification of individual target molecules in single cells of acomplex cell population while retaining cell specific informationregarding that target molecule.

In some embodiments, the invention relates to methods for identifyingwhether a plurality of targets are in a plurality of cells comprising:binding to the targets a plurality of tags, wherein a tag comprises acode that represents a) the target identity and b) the identity of thecell in which tag is binding. In some embodiments, individual cellseparation or isolation is unnecessary for the binding step. In someembodiments, tags comprise building blocks that are directly orindirectly associated with each other, for example through covalentbinding or by association through affinity. In some embodiments, tagsare formed through polymerization of building blocks in place. In someembodiments, multiple building blocks are added in a step. In someembodiment, a single building block is added at each step. In someembodiments, the cell is alive. In some embodiments, the cell is lysedor fixed.

In some embodiments, the invention relates to methods for identifying asingle cell associated with a target comprising: binding to the target atag, wherein the tag comprises a code that represents a) the target, andb) the single cell; wherein the during the binding the single cell isnot isolated from a population of cells, and wherein the code thatrepresents the single cell is unknown before the binding.

In some embodiments, the invention relates to methods for identifying asingle cell associated with a target comprising: binding to the target atag, wherein the tag comprises a code that represents a) the target, andb) the single cell; wherein the during the binding the single cell isisolated from a population of cells, and wherein the code thatrepresents the single cell is unknown before the binding.

In some embodiments, the invention further comprises detecting the code,wherein individual cell separation or isolation is unnecessary for thedetecting step. In some embodiments, each target is a protein or anucleic acid. In some embodiments, the tag is a nucleic acid or apolypeptide. In some embodiments, the tag is comprises a seriesmonomeric subunits that comprise a decipherable code. In someembodiments, the tag is a coded molecular constituent that can bedecoded. In some embodiments, the tag comprises a combination of partsthat can be decoded to determine the nature of the tag.

In some embodiments, the tag comprises a UBA. In some embodiments, theUBA is specific for one of the targets. In some embodiments, the tagcomprises a UBA. In some embodiments, the UBA comprises an antibody. Insome embodiments, the tag comprises a ESB. In some embodiments, the ESBcomprises a common linker (CL). In some embodiments, the ESB codes thetarget identity. In some embodiments, the ESB comprises a nucleic acid.In some embodiments, the tag comprises an APS. In some embodiments, theAPS is detectable a detectably distinct coding unit. In someembodiments, during the binding step multiple APSs are added to the tagin an ordered manner during successive rounds of split pool synthesis.In some embodiments, the tag comprises at least 10 APSs. In someembodiments, the APS comprises a nucleic acid. In some embodiments, thetag comprises multiple APSs, an ESB, and a UBA linked by ligation. Insome embodiments, multiple APSs, the ESB, and/or the UBA is capable ofbeing linked Click chemistry. In some embodiments, the APS or the ESBcomprises an amplification primer binding region. In some embodiments,the UBA, ESB, or APS is templatable. In some embodiment, the UBA, ESB,or APS is of a different discernable constituent (GPN: meaning one partof the code can be a nucleic acid, another can be a polypeptide, anothercan be a small molecule, etc.).

In some embodiments, the invention relates to compositions comprising:a) a first target molecule, b) a first unique binding agent (UBA)specific for the first target molecule, c) a first linkableUBA-dependent epitope specific barcode (ESB), and d) a plurality ofordered assayable polymer subunit (APS), wherein the order of APSs isdetectable. In some embodiments, the target molecule is selected fromthe group consisting of a peptide, a polypeptide, an oligopeptide, aprotein, a phosphoprotein, an antibody, a nucleic acid, a peptidenucleic acid, a synthetic small molecule, a disaccharide, atrisaccharide, an oligosaccharide, a polysaccharide, a lipid, a steroid,and a phospholipid.

In some embodiments, the invention relates to compositions comprising apopulation of particles each comprising at least a first targetmolecule, wherein the first target molecule is associated with: a) afirst unique binding agent (UBA) specific for the first target molecule,b) a first linkable UBA-dependent epitope specific barcode (ESB), and c)a first plurality of ordered assayable polymer subunits (APS), whereinthe plurality of ordered APSs associated with the first target moleculeof a first particle in the population is detectably different than theplurality of ordered APSs associated with the first target molecule of asecond particle in the population.

In some embodiments, the plurality of ordered APSs comprises 2, 3, 4, 5,6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20 APSs. In someembodiments, the plurality of ordered APSs comprises more than 20 APSs.In some embodiments, the APSs are templatable. In some embodiments, atleast one discrete particle is selected from the group consisting of acell, a liposome, an organelle, a micelle, a droplet and a bead. In someembodiments, the target molecule is selected from the group consistingof a peptide, a polypeptide, an oligopeptide, a protein, aphosphoprotein, an antibody, a nucleic acid, a peptide nucleic acid, asynthetic small molecule, a disaccharide, a trisaccharide, anoligosaccharide, a polysaccharide, a lipid, a steroid, and aphospholipid. In some embodiments, the first ESB comprises a firstcommon linker (CL). In some embodiments, said first target molecule isdirectly bound to said first UBA and said first ESB is directly bound tosaid first UBA. In some embodiments, the plurality of ordered APS isformed by stepwise addition of APSs in separate rounds. In someembodiments, the APS added on each round is linked to the first complex.In some embodiments, the linking is in order of rounds. In someembodiments, the linking is performed through binding affinity. In someembodiments, the linking of an APS, an ESB, or a UBA is performed usingchemical methods. In some embodiments, the chemical method comprisesClick chemistry. In some embodiments, the linking is performed in thepresence of Cu^(I). In some embodiments, a UBA, an APS, or an ESBcomprises nucleic acids. Some embodiments further comprise a firstlinking oligonucleotide comprising a first and a second complementaryregion to two components selected from a UBA, an APS, and an ESB. Insome embodiments, a UBA, an APS, or an ESB is linked using a linkingoligonucleotide comprising the first and the second complementary regionto two components selected from a UBA, an APS, and an ESB. Someembodiments further comprise a second linking oligonucleotide comprisinga third and a fourth complementary region to two components selectedfrom a UBA, an APS, and an ESB. In some embodiments, a UBA, an APS, oran ESB is linked using a linking oligonucleotide comprising the thirdand the fourth complementary region to two components selected from aUBA, an APS, and an ESB. In some embodiments, the second and fourthcomplementary regions are identical. In some embodiments, the second andfourth complementary regions are identical. In some embodiments, thefirst or second complementary region is shared between two APSs withinthe plurality of APSs. In some embodiments, the linking is performed byligation. In some embodiments, the linking oligonucleotide comprises asubcode encoding the origin of the APS or the ESB. In some embodiments,the APS has a subcode encoding the origin of the APS. In someembodiments, the ESB has a subcode encoding the origin of the ESB. Insome embodiments, an individual APS, ESB, or linking oligonucleotidemolecule comprises a unique counter tag. In some embodiments, uniquecounter tag is detectable. In some embodiments, the ESB is covalentlylinked to the linking oligonucleotide. In some embodiments, an APS or anESB comprises an amplification primer binding region. In someembodiments, the APSs and ESB, when linked, are capable of encoding asecondary product. In some embodiments, the secondary product is an RNAor a peptide. In some embodiments, the APSs and ESB, when linked,comprises a polymerase start site. In some embodiments, the peptidecomprises an affinity tag. In some embodiments, the affinity tag is aHis-tag. In some embodiments, the UBA, ESB, or APS is templatable. Insome embodiments, the composition further comprises a probe. In someembodiments, the probe is attached to a surface. In some embodiments,the surface comprises an array. In some embodiments, the surfacecomprises a bead. In some embodiments, the UBA is selected from thegroup consisting of antibody, peptide, aptamer, peptoid and nucleicacid. In some embodiments, the ESB is selected from the group consistingof nucleic acids, beads and chemical subunits. In some embodiments, saidAPS comprises a nucleic acid, a small molecule, or buildable complexmolecules of deterministic weight.

In some embodiments, the invention relates to kits for labeling a targetmolecule of a cell in a population of cells with a cell originationbarcode, comprising a) n sets of m assayable polymer subunits (APSs)each comprising a distinct package of information; wherein the packagesof information are capable of being linked in an ordered fashion; b) atarget molecule-specific unique binding agent (UBA).

In some embodiments, the invention relates to kits for labeling a targetmolecule of a cell in a population of cells with a cell originationbarcode, comprising a) n sets of m assayable polymer subunits (APSs)each comprising a distinct package of information; wherein the packagesof information are capable of being linked in an ordered fashion; b) aplurality of target molecule-specific unique binding agents (UBA) eachlinked with a UBA-specific epitope specific barcode (ESB).

In some embodiments, the invention relates to kits for labeling a targetmolecule of a cell in a population of cells with a cell originationbarcode, comprising a) n sets of m assayable polymer subunits (APSs)each comprising a distinct package of information; wherein the packagesof information are capable of being linked in an ordered fashion; b) aplurality of target molecule-specific unique binding agents (UBA); c) aplurality of UBA-specific epitope specific barcode (ESB), wherein eachESB is capable of linking with a designated UBA.

In some embodiments, n is 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10. In someembodiments, m is 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16,17, 18, 19, or 20. In some embodiments, n is greater than 10. In someembodiments, m is greater than 20. In some embodiments, the first ESBcomprises a first common linker (CL). In some embodiments, said ESB iscapable of directly binding to said UBA. In some embodiments, said UBAis capable of directly binding to the target molecule. In someembodiments, at least two of the assayable polymer subunit (APS) setsare identical. In some embodiments, the APSs in a first set is linkableto the APSs in a second set. In some embodiments, the APSs in a firstset is further linkable to the APSs in a second set in an orderedfashion. In some embodiments, an APS, an ESB, or a UBA is capable ofbeing linked using chemical methods. In some embodiments, the chemicalmethod comprises Click chemistry. In some embodiments, the presence ofCu^(I) is required for linkage. In some embodiments, the kit componentscan assemble through affinity binding. In some embodiments, a UBA, anAPS, or an ESB comprises nucleic acids. In some embodiments, the kitsfurther comprise a first linking oligonucleotide comprising a first anda second complementary region to two components selected from a UBA, anAPS, and an ESB. In some embodiments, the kits further comprise a secondlinking oligonucleotide comprising a third and a fourth complementaryregion to two components selected from a UBA, an APS, and an ESB. Insome embodiments, the first and third complementary regions areidentical. In some embodiments, the second and fourth complementaryregions are identical. In some embodiments, an APS, an ESB, or a UBA iscapable of being linked by ligation. In some embodiments, the linkingoligonucleotide comprises a subcode encoding the original set of the APSor the ESB. In some embodiments, the APS has a subcode encoding theorigin population of the APS. In some embodiments, the ESB has a subcodeencoding the origin population of the ESB. In some embodiments, anindividual APS, ESB, or linking oligonucleotide molecule comprises aunique counter tag. In some embodiments, the unique counter tag isdetectable. In some embodiments, the ESB is covalently linked to thelinking oligonucleotide. In some embodiments, an APS or an ESB comprisesan amplification primer binding region. In some embodiments, the APSsand ESB, when linked, are capable of encoding a secondary product. Insome embodiments, the secondary product is an RNA or a peptide. In someembodiments, the APSs and ESB, when linked, comprises a polymerase startsite. In some embodiments, the peptide comprises an affinity tag. Insome embodiments, the affinity tag is a His-tag. In some embodiments,the UBA, ESB, or APS is templatable. In some embodiments, the kitfurther comprises a probe. In some embodiments, the probe is attached toa surface. In some embodiments, the surface comprises an array. In someembodiments, the surface comprises a bead. In some embodiments, theplurality of UBAs comprises 2, 3, 4, 5, 10, 20, 30, 50, 100, 200, 300,500, 600, 700, 800, 900, 1000 or more than 1000 UBAs. In someembodiments, the plurality of UBAs comprises up to 2000 UBAs. In someembodiments, the UBA is selected from the group consisting of antibody,peptide, aptamer, peptoid and nucleic acid. In some embodiments, the ESBis selected from the group consisting of nucleic acids, beads andchemical subunits. In some embodiments, said APS comprises a nucleicacid, a small molecule, or buildable complex molecules of deterministicweight.

In some embodiments, the invention relates to methods for identifyingtarget molecules sharing a common particle origin, comprising labeling afirst plurality of targets of a first particle in a population of xparticles with a first origination barcode; and labeling a secondplurality of targets of a second particle in a population of x particleswith a second origination barcode; wherein each origination barcodecomprises a set of n assayable polymer subunits (APS); wherein each ofthe n APSs in the first and second set of APSs is selected from a groupcomprising m different APSs; and wherein the first and secondorigination barcodes are detectably different from each other with acertainty of c=1−[(1−1/x){circumflex over ( )}(m^(n))]. In someembodiments, x is greater than 1,000,000. In some embodiments, c isgreater than 99.9%. In some embodiments, c is greater than 99.99%. Insome embodiments, c is greater than 99.999%. In some embodiments, c isgreater than 99.9999%. In some embodiments, c is greater than 99.99999%.In some embodiments, n is 2, 3, 4, 5, 6, 7, 8, 9, or 10. In someembodiments, m is 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16,17, 18, 19, or 20. In some embodiments, n is greater than 10. In someembodiments, m is greater than 20.

In some embodiments, at least one discrete particle is selected from thegroup consisting of a cell, a liposome, an organelle, a micelle, adroplet and a bead. In some embodiments, the target molecule is selectedfrom the group consisting of a peptide, a polypeptide, an oligopeptide,a protein, a phosphoprotein, an antibody, a nucleic acid, a peptidenucleic acid, a synthetic small molecule, a disaccharide, atrisaccharide, an oligosaccharide, a polysaccharide, a lipid, a steroid,and a phospholipid. In some embodiments, at least two groups comprisingm different APSs are identical.

In some embodiments, n APSs are added in separate rounds. In someembodiments, the APSs of separate rounds are linked. In someembodiments, the linking is in order of rounds. In some embodiments, anappropriate n and/or m is selected based in a desired certainty levelgiven a number of cells, x.

In some embodiments, the invention relates to methods of imparting aparticle specific code to a component of a particle of a population ofparticles, the method comprising: linking a first ordered set ofassayable polymer subunits (APS) to a first component of a firstparticle of a population of particles, wherein the order of the APSs isdetectable. In some embodiments, the method further comprises detectingthe first ordered set of APSs linked with the first component, therebydetermining a particle origin of the first component. In someembodiments, the method further comprises linking a second ordered setof assayable polymer subunits (APS) to a second component of the firstparticle of a population of particles, wherein the order of the APSs isdetectable. In some embodiments, the method further comprises detectingthe second ordered set of APSs linked with the second component, therebydetermining the particle origin of the second component. In someembodiments, the first and the second ordered sets of APSs linked withthe first and second components of the first particle are the same. Insome embodiments, the method further comprises linking a third orderedset of assayable polymer subunits (APS) to a first component of secondparticle of a population of particles, wherein the order of the APSs isdetectable. In some embodiments, the first ordered set of APSs linkedwith the first component of the first particle is different than thethird ordered set of assayable polymer subunits linked with the firstcomponent of the second particle. In some embodiments, the methodfurther comprises linking a component specific epitope specific barcode(ESB) to the first component. In some embodiments, the method furthercomprises linking a component specific ESB to the second component. Insome embodiments, at least the particle is selected from the groupconsisting of a cell, a liposome, an organelle, a micelle, a droplet anda bead. In some embodiments, said at least one target molecule isdirectly bound to said first UBA and said ESB is directly bound to saidUBA. In some embodiments, at least two of the assayable polymer subunit(APS) sets are identical. In some embodiments, each APS from the orderedset of APSs is linked to the first complex. In some embodiments, thelinking is in order of rounds. In some embodiments, the UBA. ESB, or APSencodes a secondary product. In some embodiments, the secondary productis an RNA or a peptide. In some embodiments, the UBA, ESB, or APS istemplatable. In some embodiments, the ESB further comprises a uniquecounter tag. In some embodiments, the quantity of the target molecule ofthe molecule is estimated using the counter tag. In some embodiments,the APS further comprises a round-specific subcode. In some embodiments,the detection further comprises determining the presence of an APS froma designated round. In some embodiments, detection is digital. In someembodiments, detection is indirect. In some embodiments, detectingcomprises mass spectrometry. In some embodiments, detecting comprisesnucleic acid sequencing. In some embodiments, detecting comprisespeptide sequencing. In some embodiments, detecting comprises mass gelelectrophoresis. In some embodiments, detecting comprises HPLC or otherchromatographic separation. In some embodiments, detecting comprisesdetecting one or more signals associated with one or more individualAPSs. In some embodiments, the signals are ordered. In some embodiments,detecting comprises using one or more probes. In some embodiments, theprobe is attached to a surface. In some embodiments, the surfacecomprises an array. In some embodiments, the surface comprises a bead.In some embodiments, detecting comprises a separation. In someembodiments, the separation is multi-dimensional. In some embodiments,the separation resolves the first linkable UBA-dependent epitopespecific barcode (ESB) from a second linkable UBA-dependent epitopespecific barcode (ESB). In some embodiments, 3, 4, 5, 10, 20, 30, 50,100, 200, 300, 500, 600, 700, 800, 900, 1000 or more than 1000 differenttarget molecules are detected. In some embodiments, up to 2000 differenttarget molecules are detected. In some embodiments, the UBA is selectedfrom the group consisting of antibody, peptide, aptamer, peptoid andnucleic acid. In some embodiments, the ESB is selected from the groupconsisting of nucleic acids, beads and chemical subunits. In someembodiments, said APS comprises a nucleic acid, a small molecule, orbuildable complex molecules of deterministic weight. In someembodiments, the APSs are linked to through ligation or extension viapolymerization. In some embodiments, a cell origination barcode (COB) isgenerated with the APSs from the ordered set of APSs. In someembodiments, each COB in said plurality of complexes has a detectablesignal or sequence that distinguishes it from other COBs in saidpopulation of cells. In some embodiments, an APS, an ESB, or a UBA islinked using chemical methods. In some embodiments, the chemical methodcomprises Click chemistry. In some embodiments, the linking is performedin the presence of Cu^(I). In some embodiments, a UBA, an APS, or an ESBcomprises nucleic acids. In some embodiments, the linking of a UBA, anAPS, or an ESB is performed using a linking oligonucleotide thatcomprises a first and a second complementary region to two components tobe linked. In some embodiments, the first or second complementary regionis shared between APSs within a population of APSs. In some embodiments,the first or second complementary region is distinct for two differentround-specific sets of APSs. In some embodiments, the method furthercomprises ligation. In some embodiments, the target molecule is selectedfrom the group consisting of a peptide, a polypeptide, an oligopeptide,a protein, a phosphoprotein, an antibody, a nucleic acid, a peptidenucleic acid, a synthetic small molecule, a disaccharide, atrisaccharide, an oligosaccharide, a polysaccharide, a lipid, a steroid,and a phospholipid. In some embodiments, the first ESB comprises a firstcommon linker (CL). In some embodiments, the first ESB comprises a firstcommon linker (CL). In some embodiments, an individual APS, ESB, orlinking oligonucleotide molecule comprises a unique counter tag. In someembodiments, detection comprises detecting the unique counter tag. Insome embodiments, the number of unique counter tags associated with aspecific ESB is determined. In some embodiments, the number of detectedunique counter tags relate to the initial quantity of the specific ESB.In some embodiments, the ESB is covalently linked to the linkingoligonucleotide. In some embodiments, an APS or an ESB comprises anamplification primer binding region. In some embodiments, a COB encodesa peptide sequence. In some embodiments, the COB comprises a polymerasestart site. In some embodiments, the peptide comprises an affinity tag.In some embodiments, the affinity tag is a His-tag.

In some embodiments, the invention relates to methods for detectingplurality of properties originating from a plurality of discreteparticles, the method comprising: a) providing: i) a population ofparticles comprising at least a first target molecule; ii) a firstunique binding agent (UBA) specific for the first target molecule; iii)a first linkable UBA-dependent epitope specific barcode (ESB); iv) aplurality of round-specific assayable polymer subunit (APS) sets, eachset containing a plurality of APSs that are detectably distinct fromeach other; b) forming at least a first complex comprising said at leastfirst target molecule, said first UBA probe, and said first ESB; c)performing n rounds of split pool synthesis, each round comprising: i)splitting the population of particles into m reaction volumes; ii)contacting one or more reaction volumes with an APS from the APS setspecific for the round; iii) pooling two or more reaction volumes; d)detecting a plurality of properties from at least one particle from thepopulation of particles; wherein at least one of the properties relateto a quantity or an identity for a target molecule associated with theparticle.

In some embodiments, the invention relates to methods for detecting aplurality of properties originating from a plurality of discreteparticles, the method comprising: a) providing: i) a population ofparticles comprising at least a first target molecule; ii) a firstunique binding agent (UBA) specific for the first target molecule; iii)a first linkable UBA-dependent epitope specific barcode (ESB); and iv) aplurality of round-specific assayable polymer subunit (APS) sets, eachset containing a plurality of APSs that are detectably distinct fromeach other; b) forming at least a first complex comprising said at leastfirst target molecule, said first UBA probe, and said first ESB; c)performing n rounds of split pool synthesis, each round comprising: i)splitting the population of particles into m reaction volumes; ii)contacting one or more reaction volumes with an APS from the APS setspecific for the round; and iii) pooling two or more reaction volumes;d) performing another round of split pool synthesis comprising steps c)i) and c) ii); e) detecting a plurality of properties from at least oneparticle from the population of particles; wherein at least one of theproperties relate to a quantity or an identity for a target moleculeassociated with the particle.

In some embodiments, the split pool method is replaced by separation ofparticles, for example in microwells, or in microfluidic devices. Insome embodiments, separated cells are labeled with cell originationbarcodes. In some embodiments, cell origination barcodes are built inplace by stepwise addition of building blocks.

In some embodiments, n is 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14,15, 16, 17, 18, 19, or 20. In some embodiments, n is more than 20. Insome embodiments, m is different between at least two rounds. In someembodiments, m is 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16,17, 18, 19, or 20. In some embodiments, m is more than 20. In someembodiments, at least one discrete particle is selected from the groupconsisting of a cell, a liposome, an organelle, a micelle, a droplet anda bead. In some embodiments, the target molecule is selected from thegroup consisting of a peptide, a polypeptide, an oligopeptide, aprotein, a phosphoprotein, an antibody, a nucleic acid, a peptidenucleic acid, a synthetic small molecule, a disaccharide, atrisaccharide, an oligosaccharide, a polysaccharide, a lipid, a steroid,and a phospholipid. In some embodiments, the first ESB comprises a firstcommon linker (CL). In some embodiments, said at least one targetmolecule is directly bound to said first UBA and said ESB is directlybound to said UBA. In some embodiments, at least two of the assayablepolymer subunit (APS) sets are identical. In some embodiments, the APSadded on each round is linked to the first complex. In some embodiments,the linking is in order of rounds. In some embodiments, the UBA, ESB, orAPS encodes a secondary product. In some embodiments, the secondaryproduct is an RNA or a peptide. In some embodiments, the UBA, ESB, orAPS is templatable. In some embodiments, the ESB further comprises aunique counter tag. In some embodiments, the quantity of the targetmolecule of the molecule is estimated using the counter tag. In someembodiments, the APS further comprises a round-specific subcode. In someembodiments, the detection further comprises determining the presence ofan APS from a designated round. In some embodiments, detection isdigital. In some embodiments, detection is indirect. In someembodiments, detecting comprises mass spectrometry. In some embodiments,detecting comprises nucleic acid sequencing. In some embodiments,detecting comprises peptide sequencing. In some embodiments, detectingcomprises detecting one or more signals associated with one or moreindividual APSs. In some embodiments, the signals are ordered. In someembodiments, detecting comprises using one or more probes. In someembodiments, the probe is attached to a surface. In some embodiments,the surface comprises an array. In some embodiments, the surfacecomprises a bead. In some embodiments, detecting comprises a separation.In some embodiments, the separation is multi-dimensional. In someembodiments, the separation resolves the first linkable UBA-dependentepitope specific barcode (ESB) from a second linkable UBA-dependentepitope specific barcode (ESB). In some embodiments, 3, 4, 5, 10, 20,30, 50, 100, 200, 300, 500, 600, 700, 800, 900, 1000 or more than 1000different target molecules are detected. In some embodiments, up to 2000different target molecules are detected. In some embodiments, the UBA isselected from the group consisting of antibody, peptide, aptamer,peptoid and nucleic acid. In some embodiments, the ESB is selected fromthe group consisting of nucleic acids, beads and chemical subunits. Insome embodiments, said APS comprises a nucleic acid, a small molecule,or buildable complex molecules of deterministic weight. In someembodiments, the APSs are linked to through ligation or extension viapolymerization. In some embodiments, a cell origination barcode (COB) isgenerated from APSs of round specific APS sets. In some embodiments,each COB in said plurality of complexes has a detectable signal orsequence that distinguishes it from other COBs in said population ofcells. In some embodiments, an APS, an ESB, or a UBA is linked usingchemical methods. In some embodiments, the chemical method comprisesClick chemistry. In some embodiments, the linking is performed in thepresence of Cu^(I). In some embodiments, a UBA, an APS, or an ESBcomprises nucleic acids. In some embodiments, the linking of a UBA, anAPS, or an ESB is performed using a linking oligonucleotide thatcomprises a first and a second complementary region to two components tobe linked. In some embodiments, the first or second complementary regionis shared between APSs within a population of APSs. In some embodiments,the first or second complementary region is distinct for two differentround-specific sets of APSs. Some embodiments further comprise ligation.In some embodiments, the linking oligonucleotide comprises a subcodeencoding the origin population of the APS or the ESB. In someembodiments, the APS has a subcode encoding the round-specific set ofthe APS. In some embodiments, the ESB has a subcode encoding the originpresence of the ESB. In some embodiments, an individual APS, ESB, orlinking oligonucleotide molecule comprises a unique counter tag. In someembodiments, detection comprises detecting the unique counter tag. Insome embodiments, the number of unique counter tags associated with aspecific ESB is determined. In some embodiments, the number of detectedunique counter tags relate to the initial quantity of the specific ESB.In some embodiments, the ESB is covalently linked to the linkingoligonucleotide. In some embodiments, an APS or an ESB comprises anamplification primer binding region. In some embodiments, a COB encodesa peptide sequence. In some embodiments, the COB comprises a polymerasestart site. In some embodiments, the peptide comprises an affinity tag.In some embodiments, the affinity tag is a His-tag. In some embodiments,each of the reaction volumes created by the most recent splittingreceives a different APS from the APS set.

In some embodiments, the invention provides methods for detecting atleast one target molecule in a sample comprising the steps: (a)providing: (i) a population of cells potentially comprising at least onetarget molecule, (ii) a first UBA specific for a first target molecule,(iii) a first epitope specific barcode ESB specific for a region of thefirst UBA, where the ESB comprises a first common linker moiety, and(iv) a population of COB, where the population of COB comprises a secondcommon linker moiety, where the second linker moiety is complementary tothe first common linker moiety is the first ESB; (b) forming at least afirst complex comprising the at least one target molecule, the first UBAprobe, and the first ESB, where the at least one target molecule isbound to the first UBA and the ESB is bound to the UBA (c) adding thepopulation of COBs, where a second complex is formed with the least onetarget molecule, the first UBA probe, the first ESB, and a first COB,and where the second common linker moiety from the first COB is bound tothe first linker moiety from the first ESB, and where the COBs from thepopulation of COBs is associated with a cell from the population ofcells; and (d) detecting the second complex or at least part of thethird complex.

In some embodiments the invention provides methods for detecting atleast one target molecule in a sample comprising the steps: (a)providing: (i) a population of cells potentially comprising at least onetarget molecule, (ii) a first unique binding agent (UBA) specific for afirst target molecule, (iii) a first epitope specific barcode (ESB)specific for a region of the first UBA, where the ESB comprises a firstcommon linker moiety, and (iv) a population of assayable polymersubunits (APSs), where the APSs comprises a second common linker moietyand a third common linker moiety, where the second linker moiety iscomplementary to the first common linker moiety is the first ESB; (b)forming at least a first complex comprising the at least one targetmolecule, the first UBA probe, and the first ESB, where the at least onetarget molecule is bound to the first UBA and the ESB is bound to theUBA; (c) splitting the population into two or more samples; (d) addingone APS from the population of APSs per sample to the two or moresamples from step (c), where a second complex is formed with the leastone target molecule, the first UBA probe, the first ESB, and a firstAPS, and where the second common linker moiety from the first APS isbound to the first linker moiety from the first ESB; (e) pooling the twoor more samples from step (c) into one sample; (f) splitting the samplefrom step (e) into two or more samples; (g) adding one APS from thepopulation of APSs per sample to the two or more samples from step (e),where a third complex is formed with the least one target molecule, thefirst UBA probe, the first ESB, the first APS, and the second APS, wherethe second common linker moiety from the second APS is bound to thethird linker moiety from the first APS, and where the first APS and thesecond APS form a cell origination barcode (COB); and (c) detecting thethird complex or at least part of the third complex. In someembodiments, the methods further comprise repeating steps (e), through(g).

In some embodiments, the methods further comprise detecting of aplurality of target molecules by forming a plurality of complexes instep (b), each complex comprising (i) at least one target molecule (ii)a first UBA and (iii) a first epitope specific barcode (ESB) specificfor a region of the first UBA, where the ESB comprises a first commonlinker moiety, where the at least one target molecule is bound to thefirst UBA and the ESB is bound to the UBA.

In some embodiments, each COB in the plurality of complexes has adetectable signal that distinguishes it from other COB in the populationof cells.

In some embodiments, the complex is detected by sequencing or massspectrometry. In some embodiments, the third complex is detected by amethod comprising individually counting the presence of one or moremolecules of the third complex where the presence of the one or moremolecules of the third complex is indicative of the concentration of thetarget molecule in a cell. In some embodiments, the individuallydetecting further comprises detecting a digital signal.

In some embodiments, 3, 4, 5, 10, 20, 30, 50, 100, 200, 300, 500, 600,700, 800, 900, 1000 or more than 1000 different target molecules aredetected. In some embodiments, up to 2000 different target molecules aredetected.

In some embodiments, the UBA is selected from the group consisting ofantibody, peptide, aptamer, peptoid and nucleic acid. In someembodiments, the ESB is selected from the group consisting of nucleicacids, beads and chemical subunits.

In some embodiments, the APS is a nucleic acid, a small molecule, orbuildable complex molecules of deterministic weight. In someembodiments, the APS comprises a single-stranded nucleic acid hybridizedto a complementary polynucleotide sequence having attached thereto adetectable label.

In some embodiments, the first APS is attached to the first ESB throughligation or extension via polymerization. In some embodiments, thesecond APS is attached to the first APS through ligation or extensionvia polymerization.

In some embodiments, the common linker moiety is a nucleic acid. In someembodiments, the ESB is attached to the USB.

In some embodiments, said first COB comprises a plurality of APS.

Some embodiments, further comprise detecting of a plurality of targetmolecules by a method comprising: forming a plurality of complexes instep (b), each complex comprising (i) at least one target molecule (ii)a first UBA and (iii) a first epitope specific barcode (ESB) specificfor a region of said first UBA, wherein said ESB comprises a firstcommon linker moiety, wherein said at least one target molecule isassociated with said first UBA and said ESB is associated with said UBA.

In some embodiments, each COB in said plurality of complexes has adetectable signal or sequence that distinguishes it from other COBs insaid population of cells.

In some embodiments, the linking of an APS, an ESB, or a UBA isperformed using chemical methods. In some embodiments, the chemicalmethod comprises Click chemistry. In some embodiments, the linking isperformed in the presence of Cu^(I). In some embodiments, linking of anABS, an ESB, or a UBA is performed using binding affinity. In someembodiments, a UBA, an APS, or an ESB comprises nucleic acids. In someembodiments, the linking of a UBA, an APS, or an ESB is performed usinga linking oligonucleotide that comprises a first and a secondcomplementary region to two components to be linked. In someembodiments, the first or second complementary region is shared betweenAPSs within a population of APSs. In some embodiments, the first orsecond complementary region is distinct for different populations ofAPSs. Some embodiments further comprise ligation. In some embodiments,the linking oligonucleotide comprises a subcode encoding the originpopulation of the APS or the ESB. In some embodiments, the APS has asubcode encoding the origin population of the APS. In some embodiments,the ESB has a subcode encoding the origin population of the ESB. In someembodiments, an individual APS, ESB, or linking oligonucleotide moleculecomprises a unique tag. In some embodiments, detection comprisesdetecting the unique tag. In some embodiments, the number of unique tagsassociated with a specific ESB is determined. In some embodiments, thenumber of detected unique tags relate to the initial quantity of thespecific ESB. In some embodiments, the ESB is covalently linked to thelinking oligonucleotide. In some embodiments, an APS or an ESB comprisesan amplification primer binding region. In some embodiments, a COBencodes a peptide sequence. In some embodiments, the COB comprises apolymerase start site. In some embodiments, the peptide comprises anaffinity tag. In some embodiments, the affinity tag is a His-tag. Insome embodiments, the two or more samples comprise at least 5 samples.In some embodiments, the two or more samples comprise at least 10samples. In some embodiments, the two or more samples comprise at least20 samples. In some embodiments, each of the samples created by the mostrecent splitting receives a different APS.

In some embodiments, the invention relates to methods for labeling anESB linked target molecule of a cell in a population of cells with acell origination barcode (COB), comprising: separating each cell into anindividual reaction volume; and adding the COB to the ESB via chemicalor affinity means. In some embodiments, the reaction volume is selectedfrom the group consisting of a microbubble, a microdroplet, a well, amicrowell, and an enclosure in a microfluidics device.

In some embodiments, the invention relates to methods comprisingdisassociating a variety of types of components originating from a celland placing the components on a particle, wherein the components arelabeled on said particle. In some embodiments, the labeling compriseslabeling according to cell origin. In some embodiments, the labelingcomprises labeling according to component type.

In some embodiments, the signals in detection steps are ordered. In someembodiments, detecting comprises using one or more probes. In someembodiments, the probe is attached to a surface. In some embodiments,the surface comprises an array. In some embodiments, the surfacecomprises a bead. In some embodiments, detecting comprises a separation.In some embodiments, the separation is multi-dimensional.

In some embodiments, the invention provides methods for preparing atleast one UBA, ESB and/or APS as described herein.

In some embodiments, the invention provides a population of UBAs, ESBsand/or APSs as described herein. In some embodiments, the inventionprovides kits comprising a population of UBAs, ESBs and APSs asdescribed herein and instructions for its use.

INCORPORATION BY REFERENCE

All publications and patent applications mentioned in this specificationare herein incorporated by reference to the same extent as if eachindividual publication or patent application was specifically andindividually indicated to be incorporated by reference.

BRIEF DESCRIPTION OF THE DRAWINGS

The novel features of the invention are set forth with particularity inthe appended claims. A better understanding of the features andadvantages of the present invention will be obtained by reference to thefollowing detailed description that sets forth illustrative embodiments,in which the principles of the invention are utilized, and theaccompanying drawings of which:

FIG. 1 depicts quantum of information representing a distinct signature(barcode) of the cell origin for each epitope.

FIG. 2 shows a graphical representation of one embodiment of thecomponents of the epitope specific barcode and cells origin barcodes ofthe invention and their assembly.

FIG. 3 shows UBA-ESB-CL reagents of one embodiment of the invention.

FIG. 4 depicts labeling of cells in one embodiment of the invention withUBA-ESB-CL reagents.

FIG. 5 depicts ESB-COB reagents of one embodiment of the invention.

FIG. 6 depicts ESB-COB assembly according to one embodiment of theinvention.

FIG. 7 depicts ESB-COB assembly according to another embodiment of theinvention.

FIG. 8 depicts ESB-COB assembly according to another embodiment of theinvention.

FIG. 9 depicts ESB-COB assembly according to another embodiment of theinvention.

FIG. 10 depicts ESB-COB assembly according to another embodiment of theinvention.

FIG. 11 depicts a peptide based ESB-COB readout according to oneembodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

The term “nucleic acid” refers to a nucleotide polymer, and unlessotherwise limited, includes known analogs of natural nucleotides thatcan function in a similar manner (e.g., hybridize) to naturallyoccurring nucleotides.

The terms “polynucleotide”, “nucleotide”, “nucleotide sequence”,“nucleic acid” and “oligonucleotide” are used interchangeably. Theyrefer to a polymeric form of nucleotides of any length, eitherdeoxyribonucleotides or ribonucleotides, or analogs thereof.Polynucleotides may have any three dimensional structure, and mayperform any function, known or unknown. The following are non limitingexamples of polynucleotides: coding or non-coding regions of a gene orgene fragment, intergenic DNA, loci (locus) defined from linkageanalysis, exons, introns, messenger RNA (mRNA), transfer RNA, ribosomalRNA, short interfering RNA (siRNA), short-hairpin RNA (shRNA), micro-RNA(miRNA), small nucleolar RNA, ribozymes, complementary DNA (cDNA), whichis a DNA representation of mRNA, usually obtained by reversetranscription of messenger RNA (mRNA) or by amplification; DNA moleculesproduced synthetically or by amplification, genomic DNA, recombinantpolynucleotides, branched polynucleotides, plasmids, vectors, isolatedDNA of any sequence, isolated RNA of any sequence, nucleic acid probes,and primers. A polynucleotide may comprise modified nucleotides, such asmethylated nucleotides and nucleotide analogs. If present, modificationsto the nucleotide structure may be imparted before or after assembly ofthe polymer. The sequence of nucleotides may be interrupted by nonnucleotide components. A polynucleotide may be further modified afterpolymerization, such as by conjugation with a labeling component.Polynucleotide sequences, when provided, are listed in the 5′ to 3′direction, unless stated otherwise.

The term nucleic acid encompasses double- or triple-stranded nucleicacids, as well as single-stranded molecules. In double- ortriple-stranded nucleic acids, the nucleic acid strands need not becoextensive (i.e., a double-stranded nucleic acid need not bedouble-stranded along the entire length of both strands).

The term nucleic acid also encompasses any chemical modificationthereof, such as by methylation and/or by capping. Nucleic acidmodifications can include addition of chemical groups that incorporateadditional charge, polarizability, hydrogen bonding, electrostaticinteraction, and functionality to the individual nucleic acid bases orto the nucleic acid as a whole. Such modifications may include basemodifications such as 2′-position sugar modifications, 5-positionpyrimidine modifications, 8-position purine modifications, modificationsat cytosine exocyclic amines, substitutions of 5-bromo-uracil, backbonemodifications, unusual base pairing combinations such as the isobasesisocytidine and isoguanidine, and the like.

More particularly, in certain embodiments, nucleic acids, can includepolydeoxyribonucleotides (containing 2-deoxy-D-ribose),polyribonucleotides (containing D-ribose), and any other type of nucleicacid that is an N- or C-glycoside of a purine or pyrimidine base, aswell as other polymers containing normucleotidic backbones, for example,polyamide (e.g., peptide nucleic acids (PNAs)) and polymorpholino(commercially available from the Anti-Virals, Inc., Corvallis, Oreg., asNeugene) polymers, and other synthetic sequence-specific nucleic acidpolymers providing that the polymers contain nucleobases in aconfiguration which allows for base pairing and base stacking, such asis found in DNA and RNA. The term nucleic acid also encompasses linkednucleic acids (LNAs), which are described in U.S. Pat. Nos. 6,794,499,6,670,461, 6,262,490, and 6,770,748, which are incorporated herein byreference in their entirety for their disclosure of LNAs.

The nucleic acid(s) can be derived from a completely chemical synthesisprocess, such as a solid phase-mediated chemical synthesis, from abiological source, such as through isolation from any species thatproduces nucleic acid, or from processes that involve the manipulationof nucleic acids by molecular biology tools, such as DNA replication,PCR amplification, reverse transcription, or from a combination of thoseprocesses.

A nucleic acid “probe” is an oligonucleotide capable of binding to atarget nucleic acid of complementary sequence through one or more typesof chemical bonds, generally through complementary base pairing, usuallythrough hydrogen bond formation, thus forming a duplex structure. Theprobe binds or hybridizes to a “probe binding site.” The probe can belabeled with a detectable label to permit facile detection of the probe,particularly once the probe has hybridized to its complementary target.Alternatively, however, the probe may be unlabeled, but may bedetectable by specific binding with a ligand that is labeled, eitherdirectly or indirectly. Probes can vary significantly in size.Generally, probes are at least 7 to 15 nucleotides in length. Otherprobes are at least 20, 30, or 40 nucleotides long. Still other probesare somewhat longer, being at least 50, 60, 70, 80, or 90 nucleotideslong. Yet other probes are longer still, and are at least 100, 150, 200or more nucleotides long. Probes can also be of any length that iswithin any range bounded by any of the above values (e.g., 15-20nucleotides in length).

A primer or probe can be perfectly complementary to the target nucleicacid sequence or can be less than perfectly complementary. In certainembodiments, the primer has at least 65% identity to the complement ofthe target nucleic acid sequence over a sequence of at least 7nucleotides, more typically over a sequence in the range of 10-30nucleotides, and often over a sequence of at least 14-25 nucleotides,and more often has at least 75% identity, at least 85% identity, atleast 90% identity, or at least 95%, 96%, 97%. 98%, or 99% identity. Itwill be understood that certain bases (e.g., the 3′ base of a primer)are generally desirably perfectly complementary to corresponding basesof the target nucleic acid sequence. Primer and probes typically annealto the target sequence under stringent hybridization conditions.

Available binding interactions present in a mixture relying on affinitydefine specificity for two or more components' binding specificity.Generally, a high binding affinity for a first interaction in comparisonto binding affinities of other available interactions that are availablefor one or more binding partners in the first interaction will lead tohigh specificity. Binding partners with high specificity form designatedbinding partners.

Reference will now be made in detail to particularly preferredembodiments of the invention. Examples of the preferred embodiments areillustrated in the following Examples section.

Unless defined otherwise, all technical and scientific terms used hereinhave the same meaning as is commonly understood by one of skill in theart to which this invention belongs. All patents and publicationsreferred to herein are incorporated by reference in their entirety.

In some embodiments, the invention provides methods, compositions andkits for detection and quantification of individual target molecules inbiomolecular samples. In some embodiments, the invention providesmethods, compositions and kits for detection and quantification ofindividual target molecules in every cell of a complex cell populationwhile retaining cell specific information regarding that targetmolecule. Thus in some embodiments, the invention provides methods,compositions and kits for detection and quantification of individualtarget molecules in a single cell basis in samples with complex cellpopulations. Thus in some embodiments, for each cell the amount of eachtarget molecule associated with that cell is assayed. In particular theinvention provides unique binding agents that are capable of bindingindividual target molecules. The invention also provides the use ofepitope specific barcode to tag target molecules. The invention alsoprovides the use of cell origination barcodes to indicate the cell oforigin. Through epitope specific barcodes and cell origination barcodes,the binding of unique binding agents to target molecules results in theidentification of the target molecules. Methods of making and using suchunique binding agents and/or epitope specific barcodes and/or cellorigination barcodes are also provided. The methods and compositionsdescribed herein can be used in a wide variety of applications such asdiagnostic, prognostic, quality control and screening applications. Someembodiments of the invention relate to methods, compositions and kitsfor individually tagging cells.

The term “epitope” and “target molecule” are used interchangeably hereinto refer to the molecule of interest (parts of it or the whole molecule)being detected and/or quantified by the methods described herein.

Certain aspects of the invention relate to the detection of multipletarget molecules. The methods described herein provide potentialbenefits in the areas of detection of multiple target molecules,quantification, and sensitivity. In some embodiments, the inventionprovides methods and compositions for the study of multiple proteinmeasurements and/or multiple nucleic acid measurements that aresensitive and reliable.

Multiplexing within one sample at a single cell level is a key advantageof this approach. Multiplexing within one sample saves significantlabor, reduces sample quantity requirements proportional to the numberof measurements, and improves accuracy by elimination of errorscompounded by separate sample handling and measurement steps.Furthermore, obtaining measurement of multiple target molecules insingle cells in a complex cell population provides a betterunderstanding of the physiological processes within each individualcell. In some embodiments, the methods described herein allow for thepooling of different samples together during processing to be analyzedat once. This offers throughput advantages and can accelerate theanalysis of different samples.

In some embodiments, the invention provides unique binding agents (UBA)for the analysis of target molecules. In some embodiments, the inventionprovides an UBA population for use in a multiplexed assay. Each UBA inthe population is specific for a target molecule. Thus, the UBA providesthe specificity for the target molecule recognized in a cell. Thebinding of the target molecules to the UBAs is then detected usingepitope specific barcodes (ESB) and cell origination barcodes (COB).Each ESB comprises a unique code that can be associated to a specifictarget molecule. Each COB comprises a unique code that can be associatedto a specific cell of origin.

In some embodiments, the ESB are attached, directly or indirectly, tothe UBA. In other embodiments, the ESBs bind to the UBAs in a cell orsample, e.g., as part of the assay procedure. A unique COB is associatedto the UBAs in a specific cell such that each COB can be associated tothe target molecules bound to the UBAs in that cell. In someembodiments, the specific ESB/COB combination is referred as a quantumof information representing each target molecule or epitope (See FIG. 1).

In some embodiments, the COB is composed of one or more assayablepolymer subunit (APS). Certain aspects of the present invention relateto the selection of a library or population of designed (e.g., syntheticsequences) APS. In some embodiments, the present invention provides apopulation of designed (e.g. synthetic) APS wherein said APS comprisesan unique sequence and/or a detectable molecule, and wherein thecombination of one or more different APS in each COB has a detectablesignal or sequence that distinguishes it from other COBs in saidpopulation. In some embodiments, the invention provides APSs comprisingunique sequences (e.g. synthetic) that hybridize to a uniquecomplementary polynucleotide sequence having attached thereto adetectable label. In some embodiments, the APS are detected bysequencing. Accordingly, certain aspects of the present inventionprovide a population of unique COBs or ESB/COBs, each comprised of aunique APS-based combination, wherein each COBs or ESB/COBs in thepopulation is distinct from the other COBs or ESB/COBs in thepopulation. APSs generally are capable of forming a construct comprisingthe COBs. Any chemical structure allowing for such formation can be usedfor the APSs.

Unique Binding Agent (UBA)

UBAs are molecules or assemblies that are designed to bind with at leastone target molecule, at least one target molecule surrogate, or both;and can, under appropriate conditions, form a molecular complexcomprising the UBA and the target molecule. Examples of target moleculesinclude, but are not limited to, proteins, nucleic acids, lipids,carbohydrates, ions, small molecules, organic monomers, and drugs. Forconvenience only, most of the embodiments described herein are explainedin the context of UBAs that bind to a target protein or a target mRNA.However, these embodiments also can be applied to other targetmolecules. The terms “protein”, “polypeptide”, “peptide”, and “aminoacid sequence” are used interchangeably herein to refer to polymers ofamino acids of any length. The polymer may be linear or branched, it maycomprise modified amino acids, and it may be interrupted by non aminoacids or synthetic amino acids. The terms also encompass an amino acidpolymer that has been modified, for example, by disulfide bondformation, glycosylation, lipidation, acetylation, phosphorylation, orany other manipulation, such as conjugation with a labeling component.As used herein the term “amino acid” refers to either natural and/orunnatural or synthetic amino acids, including but not limited to glycineand both the D or L optical isomers, and amino acid analogs andpeptidomimetics.

UBAs comprise at least one reaction portion that allow them to bind toor interact with at least one target molecule, at least one part of atleast one target molecule, at least one target molecule surrogate, atleast part of a target molecule surrogate, or combinations thereof;typically in a sequence-specific, a confirmation-specific manner, orboth; for example but not limited to antigen-antibody binding,aptamer-target binding, and the like.

In certain embodiments, the UBAs comprise an identity portion or atleast part of an identity portion, for example, an ESB, a COB, an ESBand/or a linker oligo. In certain embodiments, the UBAs comprise acapture region. In some embodiments, the capture region is used for theisolation of the UBA and/or immobilization of the UBA into a surface.The capture region can be an affinity tag, a bead, a slide, an array, amicrodroplet, an enclosure in a microfluidic device or any othersuitable capture region in the art. In some embodiments, the captureregion is the ESB, for example the ESB can be a detectable bead such asa bead with a unique spectral signature (e.g. a bead that has beeninternally dyed with red and infrared fluorophores). Capture regions candefine reaction volumes in which manipulation of compositions of theinvention can take place.

In some embodiments, the UBA is an antibody. As used herein, the termsantibody and antibodies are used in a broad sense, to include not onlyintact antibody molecules, for example but not limited to immunoglobulinA, immunoglobulin G and immunoglobulin M, but also any immunoreactivecomponent(s) of an antibody molecule that immunospecifically bind to atleast one epitope. Such immunoreactive components include but are notlimited to, FAb fragments, FAb′ fragments. FAb′2 fragments, single chainantibody fragments (scFv), miniantibodies, diabodies, crosslinkedantibody fragments, Affibody™, cyclotides, molecules, and the like.Immunoreactive products derived using antibody engineering or proteinengineering techniques are also expressly within the meaning of the termantibodies. Detailed descriptions of antibody and/or proteinengineering, including relevant protocols, can be found in, among otherplaces, J. Maynard and G. Georgiou, Ann. Rev. Biomed. Eng. 2:339 76(2000); Antibody Engineering, R. Kontermann and S. Dubel, eds., SpringerLab Manual, Springer Verlag (2001); U.S. Pat. No. 5,831,012; and S.Paul, Antibody Engineering Protocols, Humana Press (1995).

The skilled artisan will appreciate that antibody can be obtained from avariety of sources, including but not limited to polyclonal antibody,monoclonal antibody, monospecific antibody, recombinantly expressedantibody, humanized antibody, plantibodies, and the like; and can beobtained from a variety of animal species, including rabbit, mouse,goat, rat, human, horse, bovine, guinea pig, chicken, sheep, donkey,human, and the like. A wide variety of antibodies are commerciallyavailable and custom-made antibodies can be obtained from a number ofcontract labs. Detailed descriptions of antibodies, including relevantprotocols, can be found in, among other places, Current Protocols inImmunology, Coligan et al., eds., John Wiley & Sons (1999, includingupdates through August 2003); The Electronic Notebook; Basic Methods inAntibody Production and Characterization, G. Howard and D. Bethel, eds.,CRC Press (2000); J. Goding, Monoclonal Antibodies: Principles andPractice, 3d Ed., Academic Press (1996); E. Harlow and D. Lane, UsingAntibodies, Cold Spring Harbor Lab Press (1999); P. Shepherd and C.Dean, Monoclonal Antibodies: A Practical Approach, Oxford UniversityPress (2000); A. Johnstone and M. Turner, Immunochemistry 1 and 2,Oxford University Press (1997); C. Borrebaeck, Antibody Engineering, 2ded., Oxford university Press (1995); A. Johnstone and R. Thorpe,Immunochemistry in Practice, Blackwell Science, Ltd. (1996); 11. Zola,Monoclonal Antibodies: Preparation and Use of Monoclonal Antibodies andEngineered Antibody Derivatives (Basics: From Background to Bench),Springer Verlag (2000); and S. Hockfield et al., Selected Methods forAntibody and Nucleic Acid Probes, Cold Spring Harbor Lab Press (1993).Additionally, a vast number of commercially available antibodies,including labeled or unlabeled; polyclonal, monoclonal, and monospecificantibodies, as well as immunoreactive components thereof; customantibody suppliers and the like can be found on the World Wide Web at,among other places, the Antibody Search page at biocompare.com, theAntibody Resource Page at antibodyresource.com, and the AntibodyExplorer page at sigmaaldrich.com.

In some embodiments, the antibodies described herein are attached to anucleic acid, e.g., linker oligo or a nucleic acid ESB. Methods toattach nucleic acids to antibodies are known in the art. Any suitablemethod to attach nucleic acids to antibodies is encompassed in themethods of the invention. The antibodies described herein can beattached to a nucleic acid by the methods described in Gullberg et al.,PNAS 101 (22): pages 228420-8424 (2004); and Boozer et al, AnalyticalChemistry, 76(23): pages 6967-6972 (2004), both incorporated herein byreference. The antibodies described herein can be attached to a nucleicacid by random amine attachment. In some embodiments, the antibodiesdescribed herein can be attached to a nucleic acid by random amineattachment using a 10 to 1 ratio of nucleic acid to antibody. Theantibodies described herein can be attached to a nucleic acid by themethods described in Kozlov et al., Biopolymers 5: 73 (5): pages 621-630(2004) incorporated herein by reference. The antibodies described hereincan be attached to a nucleic acid by hydrazine chemistry. The antibodiesdescribed herein can be attached to a nucleic acid using tadpoles asdescribed in Nolan, Nature Methods 2, 11-12 (2005), incorporated hereinby reference. The antibodies described herein can be attached to anucleic acid by any suitable methods known in the art to generateengineered antibodies including the ones described herein.

In some embodiments, the UBA is an aptamer. Aptamers include nucleicacid aptamers (i.e., single-stranded DNA molecules or single-strandedRNA molecules) and peptide aptamers. Aptamers bind target molecules in ahighly specific, conformation-dependent manner, typically with very highaffinity, although aptamers with lower binding affinity can be selectedif desired. Aptamers have been shown to distinguish between targetsbased on very small structural differences such as the presence orabsence of a methyl or hydroxyl group and certain aptamers candistinguish between D- and L-enantiomers. Aptamers have been obtainedthat bind small molecular targets, including drugs, metal ions, andorganic dyes, peptides, biotin, and proteins, including but not limitedto streptavidin, VEGF, and viral proteins. Aptamers have been shown toretain functional activity after biotinylation, fluorescein labeling,and when attached to glass surfaces and microspheres.

Nucleic acid aptamers, including speigelmers, are identified by an invitro selection process known as systematic evolution of ligands byexponential amplification (SELEX). In the SELEX process very largecombinatorial libraries of oligonucleotides, for example 1014 to 1015individual sequences, often as large as 60-100 nucleotides long, areroutinely screened by an iterative process of in vitro selection andamplification. Most targets are affinity enriched within 8-15 cycles andthe process has been automated allowing for faster aptamer isolation.Peptide aptamers are typically identified by several different proteinengineering techniques known in the art, including but not limited to,phage display, ribosome display, mRNA display, selectively infectedphage technology (SIP), and the like. The skilled artisan willunderstand that nucleic acid aptamers and peptide aptamers can beobtained following conventional procedures and without undueexperimentation. Detailed descriptions of aptamers, including relevantprotocols, can be found in, among other places, L. Gold, J. Biol. Chem.,270(23):13581 84 (1995); S. Jayasena, Clin. Chem., 45:1628-50 (1999); V.Sieber et al., Nat Biotechnol. 16 (10):955-60 (1998); D. Wilson and J.Szostak, Ann. Rev. Biochem. 68:611-47 (1999); L. Jermutus et al., Eur.Biophys. J., 31:179-84 (2002); S S. Spada et al., Biol. Chem.,378:445-56 (1997); B. Wlotzka et al., Proc. Natl. Acad. Sci.,99:8898-8902 (2002).

In some embodiments the aptamer will be ligated or hybridized to nucleicacid such as a linker oligo or a nucleic acid ESB. The hybridization orligation of aptamers can be done by any suitable method known in art.For example ligation can be performed enzymatically by at least one DNAligase or at least one RNA ligase, for example but not limited to, T4DNA ligase, T4 RNA ligase, Thermus thermophilus (Tth) ligase, Thermusaquaticus (Taq) DNA ligase, or Pyrococcus furiosus (Pfu) ligase.Ligation can also be performed by chemical ligation can, usingactivating and reducing agents such as carbodiimide, cyanogen bromide(BrCN), imidazole, 1-methylimidazole/carbodiimide/cystamine,N-cyanoimidazole, dithiothreitol (DTT) and ultraviolet light.

In some embodiments, the UBA is a peptoid. Peptoids are short sequencesof N-substituted glycines synthetic peptides that bind proteins. In someembodiments, small size peptoids improve diffusion and kinetics of themethods described herein. Any suitable method known in the art togenerate peptoids is encompassed in the methods described herein. SeeSimon et al., PNAS 15; 89(20): 9367-9371 (1992), incorporated herein byreference.

In some embodiments, the UBA is a nucleic acid sequence, e.g. anantisense DNA for a target mRNA. The nucleic acid sequence is preferablyat least 15 nucleotides in length, and more preferably is at least 20nucleotides in length. In specific embodiments, the target-specificsequence is about 10 to 500, 20 to 400, 30 to 300, 40 to 200, or 50 to100 nucleotides in length. In other embodiments, the target-specificsequence is about 30 to 70, 40 to 80, 50 to 90, or 60 to 100, 30 to 120,40 to 140, or 50 to 150 nucleotides in length.

Epitope Specific Barcode (ESB)

In some embodiments, the invention provides an epitope specific barcode(ESB). Each ESB comprises a unique code that can be associated to aspecific target molecule. ESBs are molecules or assemblies that aredesigned to bind with at least one UBA or part of an UBA; and can, underappropriate conditions, form a molecular complex comprising the ESB, theUBA and the target molecule.

ESBs can comprise at least one identity identification portion thatallow them to bind to or interact with at least one UBA; typically in asequence-specific, a confirmation-specific manner, or both; for examplebut not limited to UBA-antibody binding, aptamer-target binding, and thelike. In some embodiments, the ESB are attached, directly or indirectly,to the UBA. In other embodiments, the ESBs bind to the UBAs in a cell orsample, e.g., as part of the assay procedure.

In certain embodiments, the ESB is a solid surface or a capture region,for example, the ESB can be a detectable bead such as a bead with aunique spectral signature (e.g. a bead that has been internally dyedwith red and infrared fluorophores). In some embodiments, the UBA isdirectly or indirectly attached to the capture region.

In certain embodiments, the ESBs comprise common linker moiety, forexample, a linker oligo. In certain embodiments, the common linker oligois complementary to a common linker oligo in the assayable polymersubunits (APSs) that form the cell origination barcode (COB).

In certain embodiments, the ESBs comprise a capture region. In someembodiments, the capture region is used for the isolation of the ESBand/or immobilization of the ESB into a surface. The capture region canbe an affinity tag, a bead, a slide or an array. In some embodiments,the capture region is a detectable bead such as a bead with a uniquespectral signature (e.g. a bead that has been internally dyed with redand infrared fluorophores

In some embodiments, the ESB is an antibody or fragment thereof, anaptamer, a nucleic acid, or peptoid, as described above.

In some embodiments, the ESB is a nucleic acid. In some embodiments, apart of the nucleic acid is amplified with branch chain or rollingcircle approaches as known in the art.

In some embodiments, the ESB is a peptoid. Peptoids are short sequencesof N-substituted glycines synthetic peptides that bind proteins. In someembodiments, small size peptoids improve diffusion and kinetics of themethods described herein. Any suitable method known in the art togenerate peptoids is encompassed in the methods described herein. SeeSimon et al., PNAS 15; 89(20): 9367-9371 (1992), incorporated herein byreference.

In some embodiments, the ESB is a nucleic acid sequence, e.g. anantisense nucleic acid for a complementary target nucleic acid sequence.The nucleic acid sequence is preferably at least 15 nucleotides inlength, and more preferably is at least 20 nucleotides in length. Inspecific embodiments, the target-specific sequence is about 10 to 500,20 to 400, 30 to 300, 40 to 200, or 50 to 100 nucleotides in length. Inother embodiments, the target-specific sequence is about 30 to 70, 40 to80, 50 to 90, or 60 to 100, 30 to 120, 40 to 140, or 50 to 150nucleotides in length.

Cell Origination Barcode (COB)

In some embodiments, the invention provides a cell origination barcode(COB). Each COB provides a unique code that can be associated to aspecific cell of origin. In some embodiments, upon binding of the COB toa common linker moiety (e.g. common linker oligo) associated with anESB, the COB code identifies the cells of origin of the target moleculeto which the UBA/ESB complex is bound. Thus, in some embodiments theCOBs of the invention comprise two main portions: (i) a sequencespecific for a common linker moiety (e.g. common linker oligo)associated with a UBA/ESB probe; and (ii) an unique code that can beassociated to a specific cell of origin.

In some embodiments, COBs are modular structures. In some embodiments,the COB comprises a plurality of different assayable polymer subunits(APS). In some embodiments, the COBs comprise a plurality of APSsattached in linear combination. In some embodiments, a COB is amolecular entity containing certain basic elements: (i) a plurality ofAPSs comprising label attachment regions attached in linear combinationto form a backbone, and (ii) complementary polynucleotide sequences,comprising a label, which are complementary and are attached to thelabel attachment regions of the backbone. The term label attachmentregion includes a region of defined polynucleotide sequence within agiven backbone that may serve as an individual attachment point for adetectable molecule. In some embodiments, the COBs comprise a pluralityof different APSs attached in linear combination, wherein the APSscomprise small molecules of deterministic weight. In some embodiments,the COB comprises 2, 3, 4, 5, 6, 7, 8, 9, 10 or more unique APSsattached in a linear combination. In some embodiments, the COB comprises4 or more APSs attached in linear combination.

In some embodiments, the plurality of APSs attached in linearcombination can comprise uniquely designed nucleic acid sequences. Inaddition, the plurality of APSs attached in linear combination in theCOBs can comprise at least one template, for example but not limited to,at least one nucleic acid sequence, such as at least part of a linear orlinearizable viral genome, such as the genomes of adenovirus, hepatitisvirus, herpes virus, rotavirus, and the like, or bacteriophages such aslambda, M13, ϕX-174, T-series bacteriophages, and the like, includingderivatives thereof comprising cloning cassettes, polylinkers, and thelike; plasmids, such as pBR322 and pUC series plasmids, etc., includingderivatives thereof comprising cloning cassettes, polylinkers, and thelike; synthetic templates; templates comprising artificial sequences;and the like. The skilled artisan will understand that virtually anypiece of nucleic acid can serve as a template for fabricating a COBprovided that it is large enough to include at least two APSs, or it canbe combined with at least one other nucleic acid sequence so that thecombined sequence is large enough to include at least two APSs. In someembodiments, ESBs, APSs, or COBs of the invention relate to templatablebuilding blocks. In some embodiments, UBAs of the invention relate totemplatable molecules.

In some embodiments, the COB also comprises one or more APSs containinga common linker moiety (e.g. common linker oligo). The common linkermoiety can be directly or indirectly attached to the APSs. Thus, thecommon linker moiety can be covalently attached to a COB or the commonlinker moiety can be bound to the COB later in the assay. The termcommon linker moiety includes tandemly-repeated sequences of about 10 toabout 25 nucleotides. The common linker moiety can be attached at eitherthe 5′ region or the 3′ region of a COB, and may be utilized for captureand immobilization of a COB for imaging or detection, such as byattaching to a solid substrate a sequence that is complementary to thecommon linker moiety.

The elements of a COB can be found in a single molecular entity (asingular COB), or two distinct molecular entities (a dual COB). Eachmolecular entity may be composed of one molecule or more than onemolecule attached to one another by covalent or non-covalent means. Insome embodiments, each component of a dual COB has a targetmolecule-specific UBA/ESB that binds to a different site on the sametarget molecule. When using a dual COB system one of the COBs may beunlabeled. In some embodiments, the unlabeled COB may comprise a captureregion.

In various embodiments of the invention a COB is constructed fromindividual APS building blocks. In some embodiments, the APSs arecombined linearly. In some embodiments, the COB constructed from theAPSs maintains the order of the APS. In some embodiments, COBs comprisebranched structures. In some embodiments, the branched COB structurescomprise information about the order of APS addition. In variousembodiments, the individual APS forming a COB can be decoded. In someembodiments, the order or order of addition of the APSs forming the COBcan be decoded. Without being bound by theory, platforms allowing theAPS addition order to be protected and decoded lend for a higher numberof different COBs to be generated from equivalent number of APS buildingblocks. With a higher number of total COB molecule types, the likelihoodof two cells/particles in a population being labeled with the same COBdecreases. Thus, the methods of various embodiments of the inventionallow for a higher statistical significance for the determination ofcelL/particle identity.

In some embodiments, the complementary polynucleotide sequences attachedto an APS serve to attach detectable molecules, or label monomers, tothe APS. The complementary polynucleotide sequences may be directlylabeled, for example, by covalent incorporation of one or moredetectable molecules into the complementary polynucleotide sequence.Alternatively, the complementary polynucleotide sequences may beindirectly labeled, such as by incorporation of biotin or other moleculecapable of a specific ligand interaction into the complementarypolynucleotide sequence. In such instances, the ligand (e.g.,streptavidin in the case of biotin incorporation into the complementarypolynucleotide sequence) may be covalently attached to the detectablemolecule. Where the detectable molecules attached to an APS are notdirectly incorporated into the complementary polynucleotide sequence,this sequence serves as a bridge between the detectable molecule and theAPS, and may be referred to as a bridging molecule, e.g., a bridgingnucleic acid.

In some embodiments, the nucleic-acid based COBs, COB-ESB complexes, orCOB/ESB/UBA complexes of the present invention comprise nucleic acids,which may be affinity-purified or immobilized using a nucleic acid, suchas an oligonucleotide, that is complementary to a constant region of theCOB (e.g. common linker moiety, capture region or affinity tag). Asnoted above, in some embodiments the COBs comprise at least one commonlinker moiety, which may serve as an affinity tag for purificationand/or for immobilization (for example to a solid surface). The commonlinker moiety can comprises two or more tandemly-repeated regions ofrepeat nucleotides, such as a series of 15-base repeats. In suchexemplary embodiments, the COB, whether complexed to an ESB, ESB/UBA, atarget molecule/UBA/ESB or otherwise, can be purified or immobilized byan affinity reagent coated with a 15-base oligonucleotide which is thereverse complement of the repeat unit.

COBs, COB-ESB complexes, or COB/ESB/UBA complexes can be purified in twoor more affinity selection steps. For example, in the embodiments inwhich the COB is attached to an ESB/UBA complex, the COB can comprise anaffinity tag. In other embodiments when a dual COB is used, one COB cancomprise a first affinity tag and the other COB can comprise a second(different) affinity tag. The COBs are mixed with the target molecules,and complexes comprising the two probes of the dual COBs are separatedfrom unbound materials by affinity purification against one or bothindividual affinity tags.

In the first step, the mixture can be bound to an affinity reagent forthe first affinity tag, so that only probes comprising the firstaffinity tag and the desired complexes are purified. The bound materialsare released from the first affinity reagent and optionally bound to anaffinity reagent for the second affinity tag, allowing the separation ofcomplexes from COBs comprising the first affinity tag. At this pointonly full complexes would be bound. The complexes are finally releasedfrom the affinity reagent for the second affinity tag and then analyzedby the methods described herein. The affinity reagent can be any solidsurface coated with a binding partner for the affinity tag, such as acolumn, bead (e.g., latex or magnetic bead) or slide coated with thebinding partner. A variety of affinity tags known in the art may beused, e.g., to purify and/or immobilize COBs, COB-ESB complexes, orCOB/ESB/UBA complexes. In some embodiments, a biotin anchor is attachedto the COB, ESB and/or UBA, allowing immobilization of the COBs, COB-ESBcomplexes, or COB/ESB/UBA complexes on a streptavidin surface (e.g.coated slide or bead). In some embodiments, an affinity tag is attachedto a UBA, e.g., to purify and/or immobilize the UBA. An affinity tag canbe used for attachment to beads or other matrixes for a variety ofuseful applications including but not limited to purification. Examplesof affinity tags and methods of making and/or attaching them to thenucleic acids are described in U.S. Pat. No. 7,473,767; U.S. applicationSer. Nos. 10/542,458; 12/324,357; 11/645,270 and 12/541,131,incorporated herein by reference in their entirety. In some embodiments,at least two of ESB, UBAs, APSs, and COBs comprise different chemicalcompositions described herein or any other suitable composition known inthe art. For example, an ESB can comprise a peptide and/or a nucleicacid, while an APS comprises a peptide or a peptoid. Any combination ofdescribed chemistries are envisioned within the scope of the invention.

In various embodiments, ESBs, APSs and/or COBs can be template, ordered,and or decoded. In some embodiments, the order of any of these subunitsin a construct can be detected. ESBs, APSs and/or COBs can providetemplates for the addition of any of another one of ESBs, APSs and/orCOBs, for example via nucleic acid or any other suitable chemicalcomplementarity known in the art. ESBs, APSs and/or COBs may encodesecondary products, such as a nucleic acid encoding for another nucleicacid or a peptide. In some embodiments, the detection of the ESBs, APSsand/or COBs comprises decoding the same, for example generating anamplicon or expressing a peptide from the ESBs, APSs and/or COBs andsequencing or otherwise detecting the products.

The sequences, the weights or the signals provided by the label monomersassociated with the various APS of the COB of a given cell allow for theunique identification of the COB. For example, when using nucleic acidsequences, a COB having a unique identity or unique sequence signatureis associated with a UBA that recognizes a specific target molecule or aportion thereof. Detection of the COB sequence allows for the detectionof the presence of the target molecule in the mixture (qualitativeanalysis). In another example, when using fluorescent labels, a COBhaving a unique identity or unique spectral signature is associated witha UBA that recognizes a specific target molecule or a portion thereof.Detection of the COB signal, such as the spectral code of afluorescently labeled COB allows detection of the presence of the targetmolecule in the mixture (qualitative analysis). In yet another example,when using small molecules as per combinatorial synthesis procedure, aCOB having a unique deterministic weight is associated with a UBA thatrecognizes a specific target molecule or a portion thereof. Detection ofthe COB deterministic weight (e.g., via mass spectrometry) allowsdetection of the presence of the target molecule in the mixture(qualitative analysis). Counting and or quantifying the codes (e.g.sequences, label monomers, or deterministic weights) associated with agiven signature (e.g. spectral code, unique sequence, or uniquedeterministic weight) allow the counting or quantitation of all themolecules in the mixture associated the UBA coupled to the COB(quantitative analysis). UBA/ESB/COB complexes are thus useful for thediagnosis or prognosis of different biological states (e.g., disease vs.healthy) by quantitative analysis of known biological markers.

Moreover, the exquisite sensitivity of single molecule detection andquantification provided by the COBs of the invention allows for theidentification of new diagnostic and prognostic markers, including thosewhose fluctuations among the different biological states is too slightto detect a correlation with a particular biological state usingtraditional molecular methods. The sensitivity of COB-based moleculardetection permits detailed pharmacokinetic analysis of therapeutic anddiagnostic agents in small biological samples.

COB syntheses can be performed by any suitable methods known in the art,including the one described herein.

In various embodiments, the invention relates to a COB to be synthesizedby stepwise addition of assayable polymer subunits (APSs) comprisingoligonucleotides. The COB can be attached to the UBA via a common linker(CL). The CL can also be part of an oligonucleotide. In someembodiments, an epitope specific barcode is also provided as anoligonucleotide. In some instances, the epitope specific barcode can beincluded in the oligonucleotide that comprises the common linker. Insome embodiments, CL, ESB and APSs all comprise oligonucleotidesequences. Accordingly, an oligonucleotide CL may be ligated to anoligonucleotide ESB or APS. Substantially complementary or exactcomplementary annealing regions may be utilized for hybridization. Anannealing region may be provided on both ends of an oligonucleotide ESBor APS. In some embodiments, the APSs are added in various steps of asplit pool synthesis or any other suitable stepwise synthesis known inthe art. An annealing region specific to each step of a stepwisesynthesis may be incorporated into the oligonucleotides. Without beingbound by theory, if an oligonucleotide addition is skipped during astep, the step-specific annealing region of the next oligonucleotidewill not hybridize efficiently to the step-specific annealing region ofthe previous oligonucleotide that is available. Thus, the someembodiments of the invention provide methods to stall the synthesis ofCOBs missing one or more APSs.

In some embodiments, UBAs are labeled with different CLoligonucleotides, each with a unique ESB sequence specific to the UBAand a common annealing region. In many cases, the APSs are assembledinto COBs during the rounds of split pool synthesis. In these cases, ineach round, the sample is split into n different containers. A differentoligonucleotide APS can be added to each container, totaling m differentAPSs. In some embodiments n and m are the same. In other embodiments, nis greater than m or m is greater than n. Each APS can be designed sothat it will selectively hybridize an annealing region added during theround before (FIG. 6 ). In various embodiments, a pair of round-specificannealing regions is incorporated in each APS. The annealing regions canbe incorporated to each end of the APS. The annealing regionsincorporated to each end of an APS can be different. Accordingly, anannealing region of an added APS can be complementary to an availableannealing region from a previous round facilitating assembly.

In some embodiments, the APSs are stitched together and/or to a CL usingan annealing primer (FIGS. 7 and 8 ). The annealing primer may comprisea first complementary region to the CL or an APS added during theprevious round of a stepwise synthesis. The annealing primer may alsocomprise a second complementary region to the APS being added during acurrent round. Thus, the annealing primer can hybridize to twooligonucleotide subunits of subsequent rounds stitching them together.In some embodiments, the first complementary regions of annealingprimers of each round are different from the first complementary regionsof annealing primers of other rounds (FIG. 7 ). In some embodiments, thesecond complementary regions of annealing primers of each round aredifferent from the second complementary regions of annealing primers ofother rounds. In some embodiments, the first or second complementaryregions of annealing primers of different rounds are shared betweenrounds (FIG. 8 ).

In some embodiments, a CL oligonucleotide comprises pairs of loopannealing regions (FIGS. 9 and 10 ). Accordingly, APSs can be designedto hybridize to the CL in a loop geometry, hybridizing on each end tothe CL along the loop annealing regions. The loop annealing regions canbe specific to the round. The hybridization can populate the APSs alongthe CL. The APSs can be linked together using any method describedherein or other common methods known in the art. The APSs can bedesigned such that they do not efficiently hybridize to the CL along theloop annealing regions specific to other rounds. Consequently, if an APSfrom a particular round is missing, the APSs may not be linked togethersuccessfully, depending on the linking process. Alternatively, a COB maybe synthesized with a missing APS, the location of which is flanked by apair of loop annealing regions. The resulting COB can then be analyzedaccordingly and can either be discarded or the retrieved information canbe alternatively processed.

Each APS in a given round can comprise a unique subcode sequence that isdifferent from the rest of the APSs in that round (FIGS. 6-11 ). Thesubcode may comprise a unique nucleotide sequence.

A CL, or one or more APSs may further comprise a random tag regionallowing for subsequent normalization of the detected COBs (FIGS. 6-11). Variations of suitable methods making use of such random tag regionsare known in the art, e.g., see Casbon et al. (Nucleic Acids Research,2011, 39:12, c81). In some cases, the random tag region can function asa molecular counter to estimate the number of template moleculesassociated with each sequence variant. In some cases, a molecularcounter is incorporated into a CL, ESB, APS or an assembled COB prior toan amplification reaction, e.g. PCR. A library of molecular counterscomprising degenerate base regions (DBR) may be incorporated into CLs,ESBs, APSs or assembled COBs. The number of unique DBRs in a librarygenerally is limited by the length and base composition of the DBR. Forexample, a single nucleotide in a DBR would allow for four differentpossible counters, one for each base. Longer DBRs can produce highernumbers of unique counter sequences. A molecular counter from a libraryof sequences can each be incorporated in a CL, ESB, APS or an assembledCOB. The molecular counter can be used to determine whether a sequencevariant is associated with a single template molecule, or alternatively,multiple template molecules. The number of different DBR sequencesassociated with one sequence variant can serve as a direct measure ofthe number of initial template molecules. This information cansupplement or replace the information provided by read numbers of eachsequence variant, including, for example, read numbers after anamplification reaction, e.g. PCR. DBRs can also be used to determine theprobability that a sequence variant derives from a polymerase errorduring an amplification reaction or is a true original variant prior toan amplification reaction, e.g. PCR. In some embodiments, unique bindingagents (UBAs) are fixed to their targets prior to or concurrent with theassembly of COBs.

Various embodiments of the invention relate to the assembly of COBs onthe surface of cells. COBs can, for example, be assembled associatedwith UBAs targeting cell surface components. In some embodiments, UBAsare fixed to cell surface components prior to or concurrent with theassembly of COBs. In some embodiments, UBAs are delivered into cells orinto cellular compartments. In some embodiments, COBs are assembledassociated with UBAs within cells or cellular compartments. Cells may befixed prior to the addition of UBAs, ESBs or prior to COB assembly.Suitable cell permeabilization methods are known in the art and can beused to deliver components of the assay into cells and cellularcomponents.

In some embodiments, the assay is performed on bodies that are notcells. Suitable support materials known in the art, such as beads orsurface coatings, can act in the same manner a cell would act to providean original binding surface. Support materials can be decorated withbinding targets. In some embodiments, support materials spatiallyresolve binding targets from each other.

In some embodiments, the assay may comprise primary binding targets andone or more secondary binding targets that are capable of binding to theprimary target. A support material, can for example, be coated with oneor more primary targets. A library of secondary targets can be providedto bind the primary targets. UBAs can be provided to bind epitopes ofprimary and/or secondary targets. COBs can be assembled associated withthese UBAs as described for other types of targets. Inter-dependentbinding of secondary targets to primary targets can be monitored byanalyzing the COBs.

In some embodiments, multiple COBs are assembled on the same UBAmolecule.

In some embodiments, the ESBs or assembled COBs encode a derivativesequence. In some embodiments, the ESBs and/or COBs comprise apolynucleotide sequence. In some cases, the ESB and/or COB can encode anRNA sequence. In some cases, the ESB and/or the COB encode a peptidesequence. The ESB and/or the COB can encode for the peptide sequencedirectly. Alternatively, the COB can encode for a peptide sequenceindirectly, for example, through an intermediary RNA sequence. Forexample, a polynucleotide ESB or COB can encode an open reading frame.In some cases, the peptide sequence is translated after introducing theESB or COB into a construct enabling peptide expression. In someembodiments, the construct is a vector.

In some embodiments, the ESBs and COBs are assembled fromoligonucleotides. The linking agent can be a ligase. In some embodimentsthe ligase is T4 DNA ligase, using well known procedures (Maniatis, T.in Molecular Cloning, Cold Spring Harbor Laboratory (1982)). Other DNAligases may also be used. With regard to ligation, other ligases, suchas those derived from thermophilic organisms may be used thus permittingligation at higher temperatures allowing the use of longeroligonucleotides (with increased specificity) as ESBs, CLs or APSs,which could be annealed and ligated simultaneously under the highertemperatures normally permissible for annealing such oligonucleotides.The ligation, however, need not be by an enzyme and, accordingly, thelinking agent may be a chemical agent which will cause the ESB and APSsto link unless there is a nucleotide base pair mismatching at theannealing region. For simplicity, some embodiments of the invention willbe described using T4 DNA ligase as the linking agent. This enzymerequires the presence of a phosphate group on the 5′ end that is to bejoined to a 3′ OH group on a neighboring oligonucleotide.

When oligos are stacking together to bind to an annealing region with aperfect match at the junction at their ends, it results in a specificbinding to the annealing region. The CLs, ESBs and APSs can be ligatedto form an ESB linked COB. The ESB linked COBs, in turn, can be used fordetection.

In some embodiments, the ESB and/or COB assembly comprises the use ofCLICK chemistry. Suitable methods to link various molecules using CLICKchemistry are known in the art (for CLICK chemistry linkage ofoligonucleotides, see, e.g. El-Sagheer et al. (PNAS, 108:28,11338-11343, 2011).

In some embodiments, the ESB and/or COB assembly takes place inside acell. In some embodiments, the ESBs and/or APSs are first assembledinside a cell. In some embodiments, the ESBs and/or APSs are linkedinside a cell. In some embodiments, the ESBs and/or APSs are linkedoutside a cell.

In some embodiments, the assembled products are amplified and,optionally, the results are compared with amplification of similartarget nucleic acids from a reference sample. In some embodiments, theligated products of APSs are amplified and, optionally, results arecompared with amplification of a similar COB from a reference sample.Amplification can be performed by any means known in the art. In somecases, the ligated products are amplified by polymerase chain reaction(PCR). Examples of PCR techniques that can be used include, but are notlimited to, quantitative PCR, quantitative fluorescent PCR (QF-PCR),multiplex fluorescent PCR (MF-PCR), real time PCR (RTPCR), single cellPCR, restriction fragment length polymorphism PCR (PCR-RFLP),PCK-RFLPIRT-PCR-IRFLP, hot start PCR, nested PCR, in situ polonony PCR,in situ rolling circle amplification (RCA), bridge PCR, picotiter PCRand emulsion PCR. Other suitable amplification methods include theligase chain reaction (LCR), transcription amplification, self-sustainedsequence replication, selective amplification of target polynucleotidesequences, consensus sequence primed polymerase chain reaction (CP-PCR),arbitrarily primed polymerase chain reaction (AP-PCR), degenerateoligonucleotide-primed PCR (DOP-PCR) and nucleic acid based sequenceamplification (NABSA). Other amplification methods that can be usedherein include those described in U.S. Pat. Nos. 5,242.794; 5,494,810;4,988,617; and 6,582,938. In some embodiments, the amplification isperformed inside a cell.

In any of the embodiments, amplification of ligated products may occuron a support, such as a bead or a surface. In any of the embodimentsherein, COBs may be assembled on targets from a single cell.

The uniqueness of each UBA/ESB probe in a population of probes allowsfor the multiplexed analysis of a plurality of target molecules.Furthermore the uniqueness of each COB probe in a population of probesallows for the multiplexed analysis of a plurality of target moleculesin single cells.

For example, in some embodiments, each COB contains six APSs. If theAPSs are going to be sequenced and there are 20 possible uniquesequences for the APS. There will be 3.84×10⁸ possible COBs in thisexample. Thus, 3.84×10⁸ cells and their corresponding UBA/ESB probes canbe analyzed in this example. Given that in sequencing you don't have thecolor constraints present in some fluorescent methods, one can analyzemultiple UBA/ESB probes per cells. In some embodiments, 10, 15, 20, 25,30, 40, 50, 60, 65, 70, 90, 100 different UBA/ESBs are analyzed percell. In some embodiments, up to 100 different UBA/ESBs are analyzed percell. In some embodiments, up to 1000 different UBA/ESBs are analyzedper cell. In some embodiments, up to 2000 different UBA/ESBs areanalyzed per cell.

In certain embodiments, the methods of detection are performed inmultiplex assays, whereby a plurality of target molecules is detected inthe same assay (a single reaction mixture). In a preferred embodiment,the assay is a hybridization assay or an affinity binding assay in whichthe plurality of target molecules is detected simultaneously. In apreferred embodiment, the assay is hybridization assay or an affinitybinding assay in which the plurality of target molecules is detectedsimultaneously in single cells. In certain embodiments, the plurality oftarget molecules detected in the same assay is, at least 2, at least 5different target molecules, at least 10 different target molecules, atleast 20 different target molecules, at least 50 different targetmolecules, at least 75 different target molecules, at least 100different target molecules, at least 200 different target molecules, atleast 500 different target molecules, or at least 750 different targetmolecules, or at least 1000 different target molecules. In otherembodiments, the plurality of target molecules detected in the sameassay is up to 50 different target molecules, up to 100 different targetmolecules, up to 150 different target molecules, up to 200 differenttarget molecules, up to 300 different target molecules, up to 500different target molecules, up to 750 different target molecules, up to1000 different target molecules, up to 2000 target molecules, or up to5000 target molecules. In yet other embodiments, the plurality of targetmolecules detected is any range in between the foregoing numbers ofdifferent target molecules, such as, but not limited to, from 20 to 50different target molecules, from 50 to 200 different target molecules,from 100 to 1000 different target molecules, from 500 to 5000 differenttarget molecules, and so on and so forth.

In some embodiments, the detection is digital detection. In someembodiments, the detection is direct, i.e. the method acquires a signalthat is directly generated by the detected entity. In some embodiments,the detection is indirect, i.e. manipulation of an entity to be detectedtakes place before a signal is acquired. In some embodiments, aplurality of components of an entity to be detected give rise todetection signals directly or indirectly. In some embodiments, the orderof the plurality of the components can be determined through thedetection methods described herein. Such detection methods are alsodescribed as ordered detection methods or detection methods with orderedsignals.

In any of the embodiments, the detection or quantification analysis ofthe COBs can be accomplished by sequencing. The APS subunits or entireCOBs can be detected via full sequencing of all DNA tags by any suitablemethods known in the art. e.g., Illumina HiSeq 2000, including thesequencing methods described herein.

Sequencing can be accomplished through classic Sanger sequencing methodswhich are well known in the art. Sequencing can also be accomplishedusing high-throughput systems some of which allow detection of asequenced nucleotide immediately after or upon its incorporation into agrowing strand, i.e., detection of sequence in red time or substantiallyreal time. In some cases, high throughput sequencing generates at least1,000, at least 5,000, at least 10,000, at least 20,000, at least30,000, at least 40,000, at least 50,000, at least 100,000 or at least500,000 sequence reads per hour; with each read being at least 50, atleast 60, at least 70, at least 80, at least 90, at least 100, at least120 or at least 150 bases per read.

In some embodiments, high-throughput sequencing involves the use oftechnology available by Illumina's HiSeq 2000 machine. This machine usesreversible terminator-based sequencing by synthesis chemistry. Thismachine can do 200 billion DNA reads in eight days.

In some embodiments, high-throughput sequencing involves the use oftechnology available by ABI Solid System. This genetic analysis platformthat enables massively parallel sequencing of clonally-amplified DNAfragments linked to beads. The sequencing methodology is based onsequential ligation with dye-labeled oligonucleotides.

In some embodiments, high-throughput sequencing involves the use oftechnology available by Ion Torrent Personal Genome Machine (PMG). ThePGM can do 10 million reads in two hours.

In some embodiments, high-throughput sequencing involves the use oftechnology available by Helicos BioSciences Corporation (Cambridge,Mass.) such as the Single Molecule Sequencing by Synthesis (SMSS)method. SMSS is unique because it allows for sequencing the entire humangenome in up to 24 hours. This fast sequencing method also allows fordetection of a SNP nucleotide in a sequence in substantially real timeor real time. Finally, SMSS is powerful because, like the MIPtechnology, it does not require a pre amplification step prior tohybridization. In fact, SMSS does not require any amplification. SMSS isdescribed in part in U.S. Publication Application Nos. 2006002471 I;20060024678; 20060012793; 20060012784; and 20050100932.

In some embodiments, high-throughput sequencing involves the use oftechnology available by 454 Lifesciences, Inc. (Branford, Conn.) such asthe Pico Titer Plate device which includes a fiber optic plate thattransmits chemiluminescent signal generated by the sequencing reactionto be recorded by a CCD camera in the instrument. This use of fiberoptics allows for the detection of a minimum of 20 million base pairs in4.5 hours.

Methods for using bead amplification followed by fiber optics detectionare described in Marguiles, M., et al. “Genome sequencing inmicrofabricated high-density pricolitre reactors”, Nature, doi:10.1038/nature03959; and well as in U.S. Publication Application Nos.20020012930; 20030058629; 20030100102; 20030148344; 20040248161;20050079510, 20050124022; and 20060078909.

In some embodiments, high-throughput sequencing is performed usingClonal Single Molecule Array (Solexa, Inc.) or sequencing-by-synthesis(SBS) utilizing reversible terminator chemistry. These technologies aredescribed in part in U.S. Pat. Nos. 6,969,488; 6,897,023; 6,833,246;6,787,308; and U.S. Publication Application Nos. 20040106130;20030064398; 20030022207; and Constans, A., The Scientist 2003,17(13):36.

In some embodiments, high-throughput sequencing of RNA or DNA can takeplace using AnyDot.chjps (Genovoxx, Germany). In particular, theAnyDot-chips allow for 10×-50× enhancement of nucleotide fluorescencesignal detection. AnyDot.chips and methods for using them are describedin part in International Publication Application Nos. WO02/088382,WO03/020968, WO03/031947, WO2005/044836, PCT/EP05/105657,PCT/EP05/105655; and German Patent Application Nos. DE 101 49 786, DE102 14 395, DE 103 56 837, DE 10 2004 009 704, DE 10 2004 025 696, DE 102004 025 746, DE 10 2004 025 694, DE 10 2004 025 695, DE 10 2004 025744, DE 10 2004 025 745, and DE 102005 012 301.

Other high-throughput sequencing systems include those disclosed inVenter, J., et al. Science 16 Feb. 2001; Adams, M. et al, Science 24Mar. 2000; and M. J, Levene, et al. Science 299:682-686, January 2003;as well as U.S. Publication Application No. 20030044781 and2006/0078937. Overall such systems involve sequencing a target nucleicacid molecule having a plurality of bases by the temporal addition ofbases via a polymerization reaction that is measured on a molecule ofnucleic acid, i e., the activity of a nucleic acid polymerizing enzymeon the template nucleic acid molecule to be sequenced is followed inreal time. Sequence can then be deduced by identifying which base isbeing incorporated into the growing complementary strand of the targetnucleic acid by the catalytic activity of the nucleic acid polymerizingenzyme at each step in the sequence of base additions. A polymerase onthe target nucleic acid molecule complex is provided in a positionsuitable to move along the target nucleic acid molecule and extend theoligonucleotide primer at an active site. A plurality of labeled typesof nucleotide analogs are provided proximate to the active site, witheach distinguishably type of nucleotide analog being complementary to adifferent nucleotide in the target nucleic acid sequence. The growingnucleic acid strand is extended by using the polymerase to add anucleotide analog to the nucleic acid strand at the active site, wherethe nucleotide analog being added is complementary to the nucleotide ofthe target nucleic acid at the active site. The nucleotide analog addedto the oligonucleotide primer as a result of the polymerizing step isidentified. The steps of providing labeled nucleotide analogs,polymerizing the growing nucleic acid strand, and identifying the addednucleotide analog are repeated so that the nucleic acid strand isfurther extended and the sequence of the target nucleic acid isdetermined.

In various embodiments, oligonucleotide ESB or COBs are identifieddirectly. The direct identification can comprise nucleic acid sequencingdescribed supra. In some embodiments, the APS sequences encode forderivative sequences that are in turn identified. For example, apolynucleotide ESB and COB can be translated into a peptide sequence.The peptide sequence can then be identified using suitable methods knownin the art.

In some embodiments, a sequence representing a COB or ESB is identifiedusing mass spectrometric analysis. Sequencing methods comprising massspectrometry are known in the art. In various embodiments, a derivativesequence, such as a peptide, is sequenced using mass spectrometricmethods. In some embodiments, the mass spectrometric methods comprisefragmentation. In some embodiments, the mass spectrometric methodscomprise N-terminal sequencing. In some embodiments, the massspectrometric methods comprise C-terminal sequencing. In someembodiments, the mass spectrometric methods comprise Edman degradation.In various embodiments, the derivative sequence is subjected to aseparation process prior to identification. In some embodiments, theseparation process comprises chromatography. In some embodiments, theseparation process comprises HPLC. Suitable separation methods for theseparation process comprise, for example, ion-exchange chromatography orhydrophobic interaction chromatography. Ion-exchange chromatography canuse any matrix material comprising functional groups that are stronglyacidic (typically, sulfonic acid groups, e.g. sodium polystyrenesulfonate or polyAMPS), strongly basic, (quaternary amino groups, forexample, trimethylammonium groups, e.g. polyAPTAC), weakly acidic(mostly, carboxylic acid groups), or weakly basic (primary, secondary,and/or ternary amino groups, e.g. polyethylene amine). The separationmethod can, for example, use sulfonated polystyrene as a matrix, addingthe amino acids in acid solution and passing a buffer of steadilyincreasing pH through the column. Amino acids are be eluted when the pHreaches their respective isoelectric points. Hydrophobic interactionchromatography may be employed through the use of reversed phasechromatography. Many commercially available C8 and C18 silica columnshave demonstrated successful separation of peptides in solution throughthe use of an elution gradient.

In some embodiments, peptide sequences representing ESBs, APSs and theresulting COBs are designed to improve the ease of detection. In somecases, peptide sequences can be designed to improve fragmentationpatterns in a mass spectrometer. It is well known in the art that thefragmentation efficiency of a bond in a peptide sequence is sequencedependent (see, e.g. Tabb et al. Anal Chem. 2003 Mar. 1; 75(5): 1155 andKlammer et al. Bioinformatics 2008, 24: 348-356). The sequence-dependentfragmentation efficiencies can be employed to design representativepeptide sequences with desired fragmentation patterns.

In some embodiments, peptide sequences representing ESBs, APSs and theresulting COBs are designed to confer certain physical and chemicalcharacteristics to the peptide molecules. For example, representativepeptide sequences can be designed to result in peptide molecules withsolubilities in aqueous solutions within a desired range. For anotherexample, representative peptide sequences can be designed to result inpeptide molecules with a desired degree of secondary or tertiarystructure or lack thereof. For yet another example, representativepeptide sequences can be designed to result in peptide molecules withdisulfide bonds or lack thereof. For a yet further example,representative peptide sequences can be designed to result in peptidemolecules with desired binding characteristics to chosen targets. Thesequences of the ESBs, CLs, APSs and the resulting COBs can further bedesigned to exploit specially loaded tRNAs in a protein expressionsystem. Accordingly, incorporation of non-natural amino acids to theresulting peptide molecules can be accomplished.

Various embodiments relate to separating the ESB-linked COBs orderivative sequences, such as a peptide sequence, prior to detection. Insome embodiments, the separation is based on a suitable physiochemicalproperty of the molecules. These types of separations are particularlyuseful to direct the molecules to the detectors sequentially therebyincreasing their relative abundance and the complexity of the signal atthe time of the detection. Various embodiments comprise separation ofthe molecules in a sequence-targeted manner. For example, all moleculescomprising a particular ESB can be isolated by hybridizing the ESBsequence to a sufficiently complementary sequence, affinity purifyingusing an ESB-specific linked tag, affinity purifying using a derivativesequence encoded by the ESB sequence or any other suitable method knownin the art. Separation methods may also target a cell-specific COB or aportion thereof.

In some embodiments, constructs comprising ESBs and COBs are subjectedto separation. For example, the constructs can be subjected to gradientor affinity purification sorting according to the ESBs. In someembodiments, the separation may comprise multiple dimensions, forexample 2, 3, 4, 5, 6, 7, or more dimensions. For example, theconstructs can be separated sorting according to the first APSs on onedimensions and sorting the according to the second APSs on anotherdimension and optionally sorting according to the ESBs on a thirddimension.

In some embodiments, the separation method comprises separation bygradient, on a gel, using an electromagnetic field and/or any othersuitable separation method known in the art. In some embodiments,constructs comprising ESBs and/or COBs can be separated prior todetection. For example, the constructs can be separated according toESBs and the ESBs and/or COBs in the constructs can be detectedfollowing the separation. The detection can be molar ratio detection,enzymatic detection, sequencing, differential affinity in a gradient orgel, electromagnetic field, e.g. UV, fluorescence or chemiluminescence,any detection method described herein, or any other suitable detectionmethod known in the art. In some embodiments, the separation comprisesimmobilizing the constructs. For example, the constructs can beimmobilized on an array surface or on a bead. A portion of the ESBand/or COB can be used to immobilize the constructs. The ESB and/or theCOB can be detected from immobilization positions. In one example, ESBsand/or COBs comprising oligonucleotide can be immobilized on a bead ormicroarray that is coated with complementary oligonucleotides.

a. Detectable Molecules or Label Monomers

The COBs of the present invention can be labeled with any of a varietyof label monomers, such as a radioisotope, fluorochrome, dye, enzyme,nanoparticle, chemiluminescent marker, biotin, or other monomer known inthe art that can be detected directly (e.g., by light emission) orindirectly (e.g., by binding of a fluorescently-labeled antibody).Generally, one or more of the labeled APSs in the COB is labeled withone or more label monomers, and the signals provided by the labelmonomers attached to the APS of a COB constitute a detectable code thatidentifies the target to which the UBA the COB binds. In certainembodiments, the lack of a given signal from the APS (e.g., a dark spot)can also constitute part of the COB's code.

Example of label monomers that can be used with the COBs describedherein and methods to incorporate the labels monomers into the COBs aredescribed in U.S. Pat. No. 7,473,767; U.S. application Ser. Nos.10/542,458; 12/324,357; 11/645,270 and 12/541,131, incorporated hereinby reference in their entirety.

When adding detectable molecules or label monomers to the COBs, inaddition to the qualitative analytical capabilities provided by the COBof the invention and the analytical techniques based thereon, the COB ofthe invention are uniquely suitable for conducting quantitativeanalyses. By providing a one to one binding between the COB of theinvention and their target molecules in a biomolecular sample, all or arepresentative portion of the target molecules present in the sample canbe identified and counted. This individual counting of the variousmolecular species provides an accurate and direct method for determiningthe absolute or relative concentration of the target molecule in thebiomolecular sample. Moreover, the ability to address each molecule in amixture individually leverages benefits of miniaturization includinghigh sensitivity, minimal sample quantity requirements, high reactionrates which are afforded by solution phase kinetics in a small volume,and ultimately very low reagent costs.

Target Molecules

Target molecules or epitopes are the molecules detected or measured bybinding of a UBA whose target-specific region(s) recognize thereto.Examples of target molecules include, but are not limited to, proteins,nucleic acids, lipids, carbohydrates, small molecules, organic monomers,or drugs. Nucleic acids that can be analyzed by the methods hereininclude: double-stranded DNA, single-stranded DNA, single-stranded DNAhairpins, DNA/RNA hybrids, RNA (e.g. mRNA or miRNA) and RNA hairpins.For convenience only, the methods described herein are explained mostlyin the context of analyzing proteins or mRNA. However, the embodimentsdescribed herein also can be used to detect non-protein or non-mRNAtargets. In some embodiments, the target molecule is selected from thegroup consisting of a peptide, a polypeptide, an oligopeptide, aprotein, a phosphoprotein, an antibody, a nucleic acid, a peptidenucleic acid, a synthetic small molecule, a disaccharide, atrisaccharide, an oligosaccharide, a polysaccharide, a lipid, a steroid,and a phospholipid.

A target molecule can be part of a biomolecular sample that containsother components or can be the sole or major component of the sample. Atarget molecule can be a component of a whole cell or tissue, a cell ortissue extract, a fractionated lysate thereof or a substantiallypurified molecule. The target molecule can be attached in solution orsolid-phase, including, for example, to a solid surface such as a chip,microarray or bead. Also the target molecule can have either a known orunknown structure or sequence.

The compositions, methods, and kits disclosed herein can also be used ina wide variety of applications to determine the presence of targetmolecules in a sample. For example but without limitation, thecompositions, methods, and kits are useful for, pharmacokinetic studies,including but not limited to, drug metabolism, ADME profiling, andtoxicity studies; target validation for drug discovery; gene expressionprofiling, protein expression profiling; proteome analyses; metabolomicstudies; post-translation modification studies, including but notlimited to glycosylation, phosphorylation, acetylation, and amino acidmodification, such as modification of glutamate to form gamma-carboxyglutamate and hydroxylation of proline to form hydroxylation; analysesof specific serum or mucosal antibody levels, evaluation of non-nucleicacid diagnostic indicators; foreign antigen detection; and the like.

In certain embodiment, at least one UBA, at least one ESB, or both theUBA and the ESB comprise at least one antibody, aptamer or peptoid thatreacts specifically with at least one target molecule. In certainembodiments, at least one UBA, at least ESB, or both the UBA and the ESBcomprise binding proteins that specifically interact with at least onetarget molecule. In some embodiments, the ESB comprise a common linkermoiety.

The skilled artisan will appreciate that the molecular complexes and theat least part of the molecular complexes described herein can beindividually detected while tethered or attached to a substrate or whilein solution, depending on, among other things, the nature of thespecific molecular complex or cleavable component and the SMD techniqueand detection apparatus employed.

Methods

The present invention provides methods for detection and quantificationof target molecules in biomolecular samples. In particular, theinvention provides UBAs that are capable of binding individual targetmolecules. The invention also provides the use of ESBs and COBs (SeeFIG. 2 ). Through the ESBs' and COBs' codes, the binding of the UBAs totarget molecules results in the identification of the target moleculesin single cells. In some embodiments, the ESB/COB complex represents aquantum of information that represents the target molecule and the cellof origin (See FIG. 1 ). Methods of making and using such UBAs and/orESBs and COBs are also provided.

In one aspect, the invention provides methods to identify, multipletarget molecules in every cell of a complex cell population and toretain cell specific information regarding that target molecule.Therefore, for each cell the amount of each target molecule associatedwith that cell is assayed. In some embodiments, multiple quanta ofinformation are determined to identify multiple target molecules inevery cell of a complex cell population.

In some embodiments, the invention provides methods for detecting atleast one target molecule in a sample comprising the steps: (a)providing: (i) a population of cells potentially comprising at least onetarget molecule, (ii) a first UBA specific for a first target molecule,(iii) a first epitope specific barcode ESB specific for a region of thefirst UBA, where the ESB comprises a first common linker moiety, and(iv) a population of COB, where the population of COB comprises a secondcommon linker moiety, where the second linker moiety is complementary tothe first common linker moiety is the first ESB; (b) forming at least afirst complex comprising the at least one target molecule, the first UBAprobe, and the first ESB, where the at least one target molecule isbound to the first UBA and the ESB is bound to the UBA (c) adding thepopulation of COBs, where a second complex is formed with the least onetarget molecule, the first UBA probe, the first ESB, and a first COB,and where the second common linker moiety from the first COB is bound tothe first linker moiety from the first ESB, and where the COBs from thepopulation of COBs is associated with a cell from the population ofcells; and (d) detecting the second complex or at least part of thethird complex.

In some embodiments, the invention provides methods for detection and/orquantification of a target molecule by binding a UBA to a targetmolecule. A UBA comprises at least one reaction portion that allow theUBA to bind to or interact with the target molecule; typically in asequence-specific, a confirmation-specific manner, or both; for examplebut not limited to antigen-antibody binding, aptamer-target binding, andthe like (See FIGS. 2 and 3 ).

In some embodiments, UBAs can be part of at least one probe set,comprising at least one first probe and at least one second probe. Thus,in some embodiments the invention provides methods for detection and/orquantification of a target molecule by binding a UBA probe set to atarget molecule, where the UBA probe set comprises a first UBA probe anda second UBA probe. The first UBA probe and the second UBA probecomprise at least one reaction portion that allow the probes to bind toor interact with different regions of the target molecule, e.g., in asequence-specific manner, a confirmation-specific manner, or both. Insome embodiments, the UBA probe and/or a second UBA probe contain acapture region as described herein.

In certain embodiments, the UBAs comprise an identity portion or atleast part of an identity portion, for example, an ESB, a COB, an ESBand/or a linker oligo. The identity portion allows for theidentification of the presence or absence of the UBAs bound to thetarget molecule in the detection step of the methods described herein.Thus, in some embodiments the invention provides methods for detectionand/or quantification of a target molecule by binding the UBA to atarget molecule, wherein UBA contains an identity portion (e.g., ESB, aCOB, an ESB and/or a linker oligo).

In some embodiments, the target molecule is tagged within cellsindirectly with an epitope specific barcode (ESB). Each ESB comprises aunique code that can be associated to a specific target molecule. ESBsare molecules or assemblies that are designed to bind with at least oneUBA or part of an UBA; and can, under appropriate conditions, form amolecular complex comprising the ESB, the UBA and the target molecule.ESBs comprise at least one identity identification portion that allowthem to bind to or interact with at least one UBA; typically in asequence-specific, a confirmation-specific manner, or both; for examplebut not limited to UBA-antibody binding, aptamer-target binding, and thelike. In some embodiments, the ESB are attached, directly or indirectly,to the UBA. In other embodiments, the ESBs bind to the UBAs in a cell orsample, e.g., as part of the assay procedure. In certain embodiments,the UBAs and/or ESBs comprise a capture region. In some embodiments, thecapture region is used for the isolation of the UBA/ESB and/orimmobilization of the UBA/ESB into a surface. The capture region can bean affinity tag, a bead, a slide or an array. In certain embodiments,the ESBs comprise common linker moiety, for example, a linker oligo. Incertain embodiments, the common linker oligo is complementary to acommon linker oligo in the assayable polymer subunits (APSs) that formthe cell origination barcode (COB).

FIGS. 3 and 4 show a schematic representation of one of the embodimentsof the invention in which a split pool synthesis approach is used toappend the COB to the target molecule/UBA/ESB complex. FIG. 3 in Step 1shows the labeling of cells with UBA-ESB-CL reagents. The UBA providesthe specificity for the target molecule to be recognized in a cell. Insome embodiments, the UBA can be an antibody specific for a surfacemarker like CD8, or an intracellular epitope like a phospho-epitope on akinase such as Stat-3. In some embodiments, the UBA could be anantisense DNA for a target mRNA in a fixed cell. The UBA is identifiedwith an ESB that has a CL moiety, the latter for later addition of cellspecific tagging information. FIG. 4 is Step 2 shows the start of thesplit pool synthesis. In this example, the cell population is split into20 tubes. Cell populations can be split into wells, bead or any suitablesurfaces known in the art. In Step 3 an APS unit is added to each tube.The APS binds the UBA/ESB complex via the complementary CLs in the APSand the ESB. In Step 4, each cell in a given tube now has appended toeach UBA-ESB pair the same subunit as defined by the tube contents (oneof 1-20 APS in this example). Each split population from Step 3 now hasa DAPS “tag” polymer subunit added to all DBAAs in that cell. In Step 5,the cells from the 20 tubes are pulled into one tube. 1/20 of the cellshave the same APS subunit. In Step 6, steps 2-4 are repeated to add asecond APS to the prior APS. In this example, cells in one tube willhave a mixture of cells all of which have the APS subunit from the round2 and one of the 20 APSs used in round 1 in a statistically equaldistribution. Thus, in round two within each individual tube mixture allpolymers are extended by the addition of the same APS. The process isrepeated as needed. The epitope/barcode along with linked cell originsignature is read by any methods known in the art including the onesdescribed herein.

The number of split pool rounds required is defined by the number ofcells in an assay and a statistical estimate of what would give anover-representation of the number of tags that ensure unique COB foreach cell. This is given by the following equation:Number of tags required is ln(1−C)/ln(1−1/N) where C=certainty ofover-representation and where N=number of cells

Thus, if you have 1 million cells, and you want 99.9% certainty of taguniqueness, you need:ln(0.001)/ln(1− 1/10⁶)=6,907,751Or approximately 7 million tags. In various embodiments, a highcertainty of tag uniqueness ensures a high statistical significance foridentification of cells/particles as distinct entities. Without beingbound by theory, a high certainty of tag uniqueness provides for a highlikelihood that two identical COB labels originated from the samecell/particle.

However, for 10⁶ cells, 7 million tags means 1000 cell pairs could belabeled as the “same” cell. Therefore, to have only a 1 in 10 chancethere is a SINGLE pair of duplicate cells, the equation should be set to99.99999%ln(1−0.9999999)/ln(1− 1/10⁶)=16,118,087Thus requiring 16-fold more tags than cells.

To determine the number of rounds given a given number of subunits forbarcode creation:x ^(y)=T gives y=ln(T)/ln(x)If you had 20 subunits, for 1.7×10⁷ tags you need the following APSaddition cycles:ln(17,000,000)/ln(20)=5.557This can be round up to 6 APS addition cycles.If you had 100 subunit %, you would need only 3.6 rounds, or round-up to4 APS addition cycles.

Thus, in some embodiments, the invention provides methods for taggingtarget molecules within cells indirectly with an ESB. The cellpopulation is treated in a split pool synthesis approach that appends tothe epitope specific barcode a second signature that indicates the cellof origin, or a cell origin barcode. UBAs can be antibodies, diabodies,etc. for proteins, or anti-sense DNA tags for RNA and DNA for nucleicacids. ESB can be nucleic acids readable by high throughput sequencingapproaches or chemical subunits assayable by mass spectrometryapproaches. COBs can be nucleic acids readable by high throughputsequencing approaches or chemical subunits assayable by massspectrometry approaches.

The APS can be specific strands of DNA or DNA-mimics. The APSs can belinked via ligase. Example of enzymes that can be used for ligationinclude but are not limited to DNA ligase, and RNA ligase such as T4 DNAligase, T4 RNA ligase, Thermus thermophilus (Tth) ligase, Thermusaquaticus (Taq) DNA ligase, or Pyrococcus furiosus (Pfu) ligase.Chemical ligation can be performed using activating and reducing agentssuch as carbodiimide, cyanogen bromide (BrCN), imidazole,1-methylimidazole/carbodiimide/cystamine, N-cyanoimidazole,dithiothreitol (DTT) and ultraviolet light. Also within the scope of theinvention are ligation techniques such as gap-filling ligation,including, without limitation, gap-filling OLA and LCR, bridgingoligonucleotide ligation, and correction ligation. Descriptions of thesetechniques can be found, among other places, in U.S. Pat. No. 5,185,243,published European Patent Applications EP 320308 and EP 439182, and PCTPublication Nos. WO 90/01069 and WO 01/57268. The APSs can be extendedvia polymerases.

These APS subunits can be detected via full sequencing of all DNA tagsby any suitable methods known in the art, e.g., Illumina HiSeq 2000,including the sequencing methods described herein.

The APS can be small molecules as per combinatorial synthesis proceduresor buildable complex molecules of deterministic weights. These subunitscan be detected via mass spectrometry

Thus in some embodiments, the cell-specific information is assembled viaa UBA (barcode for the epitope to be recognized) as linked to itsassociated COB (from which cell the information originated) (See FIG. 5).

In some embodiments, the UBA/ESB/COB complexes are isolated via acapture region as described herein. In some embodiments, the captureregion is uses for the immobilization of the UBA/ESB/COB complexes intoa surface.

In some embodiments, the information on UBAs can be amplified prior tothe then COB procedure (split pool) with any suitable amplificationtechnique known in the art, including the ones described herein suchbranch chain or rolling circle approaches.

In some embodiments, error correction & detection can be encoded intosubunits. The general idea for achieving error detection and correctionis to add some redundancy (i.e., some extra data) to a message, whichreceivers can use to check consistency of the delivered message, and torecover data determined to be erroneous. Error-detection and correctionschemes can be either systematic or non-systematic: In a systematicscheme, the transmitter sends the original data, and attaches a fixednumber of check bits (or parity data), which are derived from the databits by some deterministic algorithm. If only error detection isrequired, a receiver can simply apply the same algorithm to the receiveddata bits and compare its output with the received check bits; if thevalues do not match, an error has occurred at some point during thetransmission. In a system that uses a non-systematic code, the originalmessage is transformed into an encoded message that has at least as manybits as the original message. Error detection and correction schemesinclude repetition codes, parity bits, checksums, cyclic redundancychecks (CRCs), cryptographic hash functions, error-correcting codes,automatic repeat request, Hybrid ARQ, error-correcting code,convolutional codes, block codes such as hamming codes, multidimensionalparity-check codes, Reed-Solomon codes, turbo codes and low-densityparity-check codes (LDPC).

In some embodiments, the chains at each round are blocked from furtheraddition if polymers did not add. This could be accomplished with DNA aspolymer units if each round one uses different overhangs forcomplementary additions.

In some embodiments, the epitope/barcode along with linked cell originsignature is read by sequencing using methods known in the art,including the ones described herein. The sensitivity for the sequencingapproach assuming that each 100 bp read represents an ESB-COB pair is asfollows for target proteins. The protein copy numbers of molecules ofinterest range from 100 to 100,000. Assuming that one will want to read100 proteins with the following rough distribution:

Test 1 Test 1 Test 2 Test 2 proteins reads proteins reads   100 copies20 2 × 10³ 20 2 × 10³   500 copies 20 1 × 10⁴ 20 1 × 10⁴  1000 copies 202 × 10⁴ 20 2 × 10⁴  10000 copies 20 2 × 10⁵ 40 4 × 10⁵ 100000 copies 202 × 10⁶  0

In Test 1 one will need to be able to read 2,232,000 sequences per cellthen to access all 100 proteins in a cell. Using a sequencing techniquethat can do 2×10⁹ reads such as Illumina HiSeq 2000, this means theapproach can read 100 proteins in ˜1000 cells. However, if one limitsthe high copy number proteins by avoiding them altogether or “capping”their representation by normalization (several approaches can work forthis), we can increase the cell number accessible. Say one thereforenormalize and cap the 100,000 copies to a 10,000 copy limit (Test 2),then the total number of reads is 432,000. That is one can read 100proteins in ˜5000 cells.

For mRNA the numbers are different, since RNAs are typically expressedmuch lower. The RNA copy numbers of molecules of interest range from 5to 1000 (based on Lewin's Essential Genes numbers); not countingspecialized mRNAs for high protein production like actin or Ig. Thus,assuming one wants to read 100 mRNAs with the following roughdistribution:

Test 1 mRNAs Test 1 reads   5 copies 60  300  50 copies 20  1000  100copies 10  1000 1000 copies 10 10000

In Test 1 one needs to be able to read 12,300 sequences per cell toaccess all 100 mRNAs in a cell. Using a sequencing technique that can do2×10⁹ reads such as Illumina HiSeq 2000, this means the approach canread 100 mRNAs in ˜162,000 cells. This is equivalent to a high parameterflow cytometry run. 200 mRNAs with the same distribution could scalelinearly to be read on ˜80,000 cells.

As it will be evident to those skilled in the art increasing the numberof reads will increase the cell number and parameters accessible (e.g.,mRNAs or proteins).

Any of the embodiments described herein can be used in the detection ofmultiple target molecules. In some embodiments, the invention providesmethods comprising UBA for the analysis of target molecules. In someembodiments, the invention provides a UBA population for use in amultiplexed assay. Each UBA in the population is specific for a targetmolecule. The binding of the target molecules to the UBAs is thendetected using ESB-COB pairs. Each ESB-COB pair comprises a unique labelcode that can be associated to a specific target molecule and the cellof origin as described herein.

In some embodiments, the detection of the ESB-COB as described below isdigital in nature in that one molecule at a time is counted. Whilefluorescence is used to read the code, the signals are high and the spotis either present of not, thus the digital detection. Using digitaldetection rather than an analogue fluorescent signal used to quantifysignal leads to more accurate quantification. Thus the methods describedherein allows for multiplexing to levels beyond currently possible, formore accurate quantification, and possibly higher sensitivity.

Biomolecular Samples

The UBA and ESB/COB systems of the invention can be used to detecttarget molecules in any biomolecular sample. As will be appreciated bythose in the art, the sample may comprise any number of things,including, but not limited to: biological samples, such as cells(including both primary cells and cultured cell lines), cell lysates, orextracts, tissues and tissue extracts; bodily fluids (including, but notlimited to, blood, urine, serum, lymph, bile, cerebrospinal fluid,interstitial fluid, aqueous or vitreous humor, colostrum, sputum,amniotic fluid, saliva, anal and vaginal secretions, perspiration andsemen, a transudate, an exudate (e.g., fluid obtained from an abscess orany other site of infection or inflammation) or fluid obtained from ajoint (e.g., a normal joint or a joint affected by disease such asrheumatoid arthritis, osteoarthritis, gout or septic arthritis) ofvirtually any organism, with mammalian samples being preferred and humansamples being particularly preferred; environmental samples (including,but not limited to, air, agricultural, water and soil samples);biological warfare agent samples; research samples includingextracellular fluids, extracellular supernatants from cell cultures,inclusion bodies in bacteria, cellular compartments, cellular periplasm,mitochondria compartment, etc.

The biomolecular samples can be indirectly derived from biologicalspecimens. For example, where the target molecule of interest is aprotein kinase the biomolecular sample of the invention can be a samplecontaining isolated proteins from a cell lysate. In another example, thebiomolecular sample of the invention is generated by subjecting abiological specimen to fractionation, e.g., size fractionation ormembrane fractionation.

Protein isolation techniques are also well known in the art and kitsemploying at least some of these techniques are commercially available.Protein isolation techniques typically employ one or more of thefollowing: maceration and cell lysis, including physical, chemical andenzymatic methods; centrifugation; separations by molecular weight, suchas size exclusion chromatography and preparative electrophoresis;selective precipitation, for example, salting-in and salting-outprocedures; various chromatographic methods; and the like. Detaileddescriptions of and relevant protocols for protein purificationtechniques can be found in, among other places, Marchak et al.,Strategies for Protein Purification and Characterization: A LaboratoryCourse Manual, Cold Spring Harbor Press (1996); Essentials from Cells: ALaboratory Manual, D. Spector and R. Goldman, eds., Cold Spring HarborPress (2003); R. Simpson, Proteins and Proteomics: A Laboratory Manual,Cold Spring Harbor Press (2003); and D. Liebler, Introduction toProteomics, Humana Press (2002). Commercially available kits can also beused, for example but not limited to, ProteoExtract.™. Partial ProteomeExtraction Kits (P-PEK) and ProteoExtract.™. Complete ProteomeExtraction Kits (C-PEK), available from CALBIOCHEM.®, La Jolla, Calif.The skilled artisan will appreciate that non-nucleic acid analytes foruse with the inventive compositions, methods, and kits can be readilyobtained without undue experimentation using such purificationtechniques and commercial kits

The biomolecular samples of the invention may be either native, e.g.,not subject to manipulation or treatment, or treated, which can includeany number of treatments, including exposure to candidate agentsincluding drugs, genetic engineering (e.g., the addition or deletion ofa gene), etc.

Biomolecular samples may also include environmental samples, such asthose containing bacteria or other organisms, such as diatoms,dinoflagellates, algae, among others, such as in certain marine orearth-based samples.

Detection of COBs

COBs/ESB complexes are detected by any means available in the art thatis capable of detecting the specific sequences or signals on a givenCOBs/ESB complex.

In some embodiments, the information on the UBA, ESB, COB, UBA/ESBcomplexes, UBA/ESB/COB complexes COB/ESB complexes and/or a combinationthereof can be amplified. Amplification can be performed by any meansknown in the art. In some cases, the information on the UBA, ESB, COB,UBA/ESB complexes, UBA/ESB/COB complexes COB/ESB complexes and/or acombination thereof are amplified by polymerase chain reaction (PCR).Examples of PCR techniques that can be used include, but are not limitedto, quantitative PCR, quantitative fluorescent PCR (QF-PCR), multiplexfluorescent PCR (MF-PCR), real time PCR (RT-PCR), single cell PCR,restriction fragment length polymorphism PCR (PCR-RFLP),PCR-RFLP/RT-PCR-RFLP, hot start PCR, nested PCR, in situ polonony PCR,in situ rolling circle amplification (RCA), bridge PCR, picotiter PCRand emulsion PCR. Other suitable amplification methods include theligase chain reaction (LCR), transcription amplification, self-sustainedsequence replication, selective amplification of target polynucleotidesequences, consensus sequence primed polymerase chain reaction (CP-PCR),arbitrarily primed polymerase chain reaction (AP-PCR), degenerateoligonucleotide-primed PCR (DOP-PCR) and nucleic acid based sequenceamplification (NABSA). Other amplification methods that can be usedherein include those described in U.S. Pat. Nos. 5,242,794; 5,494,810;4,988,617; and 6,582,938.

In any of the embodiments, amplification of the information on the UBA,ESB, COB, UBA/ESB complexes, UBA/ESB/COB complexes COB/ESB complexesand/or a combination thereof may occur on a bead. In any of theembodiments herein, target nucleic acids may be obtained from a singlecell.

In any of the embodiments herein, the information on the UBA, ESB, COB,UBA/ESB complexes, UBA/ESB/COB complexes COB/ESB complexes and/or acombination thereof can be pre-amplified prior to the amplification step(e.g., PCR).

In some embodiments the UBA. ESB, COB, UBA/ESB complexes, UBA/ESB/COBcomplexes COB/ESB complexes and/or a combination thereof are quantified.Methods for quantifying nucleic acids are known in the art and include,but are not limited to, gas chromatography, supercritical fluidchromatography, liquid chromatography (including partitionchromatography, adsorption chromatography, ion exchange chromatography,size-exclusion chromatography, thin-layer chromatography, and affinitychromatography), electrophoresis (including capillary electrophoresis,capillary zone electrophoresis, capillary isoelectric focusing,capillary electrochromatography, micellar electrokinetic capillarychromatography, isotachophoresis, transient isotachophoresis andcapillary gel electrophoresis), comparative genomic hybridization (CGH),microarrays, bead arrays, and high-throughput genotyping such as withthe use of molecular inversion probe (MIP).

Quantification of the UBA, ESB, COB, UBA/ESB complexes, UBA/ESB/COBcomplexes COB/ESB complexes and/or a combination thereof can be used todetermine gene/or allele copy number, gene or exon-level expression,methylation-state analysis, or detect a novel transcript in order todiagnose or condition, i.e. fetal abnormality or cancer.

In some embodiments the UBA, ESB, COB, UBA/ESB complexes, UBA/ESB/COBcomplexes COB/ESB complexes and/or a combination thereof are sequenced.Sequencing can be accomplished through classic Sanger sequencing methodswhich are well known in the art. Sequence can also be accomplished usinghigh-throughput systems some of which allow detection of a sequencednucleotide immediately after or upon its incorporation into a growingstrand, i.e., detection of sequence in real time or substantially realtime. In some cases, high throughput sequencing generates at least1,000, at least 5,000, at least 10,000, at least 20,000, at least30,000, at least 40,000, at least 50,000, at least 100,000 or at least500,000 sequence reads per hour; with each read being at least 50, atleast 60, at least 70, at least 80, at least 90, at least 100, at least120 or at least 150 bases per read.

In some embodiments, high-throughput sequencing involves the use oftechnology available by Illumina's HiSeq 2000 machine. This machine usesreversible terminator-based sequencing by synthesis chemistry. Thismachine can do 200 billion DNA reads in eight days.

In some embodiments, high-throughput sequencing involves the use oftechnology available by ABI Solid System. This genetic analysis platformthat enables massively parallel sequencing of clonally-amplified DNAfragments linked to beads. The sequencing methodology is based onsequential ligation with dye-labeled oligonucleotides.

In some embodiments, high-throughput sequencing involves the use oftechnology available by Ion Torrent Personal Genome Machine (PMG). ThePGM can do 10 million reads in two hours.

In some embodiments, high-throughput sequencing involves the use oftechnology available by Helicos BioSciences Corporation (Cambridge,Mass.) such as the Single Molecule Sequencing by Synthesis (SMSS)method. SMSS is unique because it allows for sequencing the entire humangenome in up to 24 hours. Finally, SMSS is described in part in U.S.Publication Application Nos. 20060024711; 20060024678; 20060012793;20060012784; and 20050100932.

In some embodiments, high-throughput sequencing involves the use oftechnology available by 454 Lifesciences, Inc. (Branford, Conn.) such asthe PicoTiterPlate device which includes a fiber optic plate thattransmits chemiluminescent signal generated by the sequencing reactionto be recorded by a CCD camera in the instrument. This use of fiberoptics allows for the detection of a minimum of 20 million base pairs in4.5 hours.

Methods for using bead amplification followed by fiber optics detectionare described in Marguiles, M., et al. “Genome sequencing inmicrofabricated high-density pricolitre reactors”, Nature,doi:10.1038/nature03959; and well as in U.S. Publication ApplicationNos. 20020012930; 20030068629; 20030100102; 20030148344; 20040248161;20050079510, 20050124022; and 20060078909.

In some embodiments, high-throughput sequencing is performed usingClonal Single Molecule Array (Solexa, Inc.) or sequencing-by-synthesis(SBS) utilizing reversible terminator chemistry. These technologies aredescribed in part in U.S. Pat. Nos. 6,969,488; 6,897,023; 6,833,246;6,787,308; and U.S. Publication Application Nos. 20040106110;20030064398; 20030022207; and Constans, A., The Scientist 2003,17(13):36.

In some embodiments, high-throughput sequencing can take place usingAnyDot.chips (Genovoxx, Germany). In particular, the AnyDot.chips allowfor 10×-50× enhancement of nucleotide fluorescence signal detection.AnyDot.chips and methods for using them are described in part inInternational Publication Application Nos. WO 02088382, WO 03020968, WO03031947, WO 2005044836, PCT/EP 05/05657, PCT/EP 05/05655; and GermanPatent Application Nos. DE 101 49 786, DE 102 14 395, DE 103 56 837, DE10 2004 009 704, DE 10 2004 025 696, DE 10 2004 025 746, DE 10 2004 025694, DE 10 2004 025 695, DE 10 2004 025 744, DE 10 2004 025 745, and DE10 2005 012 301.

Other high-throughput sequencing systems include those disclosed inVenter, J., et al. Science 16 Feb. 2001; Adams, M. et al. Science 24Mar. 2000; and M. J. Levene, et al. Science 299:682-686, January 2003;as well as U.S. Publication Application No. 20030044781 and2006/0078937. Overall such system involve sequencing a target nucleicacid molecule having a plurality of bases by the temporal addition ofbases via a polymerization reaction that is measured on a molecule ofnucleic acid, i.e. the activity of a nucleic acid polymerizing enzyme onthe template nucleic acid molecule to be sequenced is followed in realtime. Sequence can then be deduced by identifying which base is beingincorporated into the growing complementary strand of the target nucleicacid by the catalytic activity of the nucleic acid polymerizing enzymeat each step in the sequence of base additions. A polymerase on thetarget nucleic acid molecule complex is provided in a position suitableto move along the target nucleic acid molecule and extend theoligonucleotide primer at an active site. A plurality of labeled typesof nucleotide analogs are provided proximate to the active site, witheach distinguishable type of nucleotide analog being complementary to adifferent nucleotide in the target nucleic acid sequence. The growingnucleic acid strand is extended by using the polymerase to add anucleotide analog to the nucleic acid strand at the active site, wherethe nucleotide analog being added is complementary to the nucleotide ofthe target nucleic acid at the active site. The nucleotide analog addedto the oligonucleotide primer as a result of the polymerizing step isidentified. The steps of providing labeled nucleotide analogs,polymerizing the growing nucleic acid strand, and identifying the addednucleotide analog are repeated so that the nucleic acid strand isfurther extended and the sequence of the target nucleic acid isdetermined.

In some embodiments, sequence analysis of the UBA, ESB, COB, UBA/ESBcomplexes, UBA/ESB/COB complexes COB/ESB complexes and/or a combinationthereof may include a four-color sequencing by ligation scheme(degenerate ligation), which involves hybridizing an anchor primer toone of four positions. Then an enzymatic ligation reaction of the anchorprimer to a population of degenerate nonamers that are labeled withfluorescent dyes is performed. At any given cycle, the population ofnonamers that is used is structure such that the identity of one of itspositions is correlated with the identity of the fluorophore attached tothat nonamer. To the extent that the ligase discriminates forcomplementarity at that queried position, the fluorescent signal allowsthe inference of the identity of the base. After performing the ligationand four-color imaging, the anchor primer:nonamer complexes are strippedand a new cycle begins. Methods to image sequence information afterperforming ligation are known in the art.

One or more UBA, ESB, COB, UBA/ESB complexes, UBA/ESB/COB complexesCOB/ESB complexes and/or a combination thereof complexes can be detectedand/or quantified by any method that detects and/or quantifies thepresence of the assembled detection complex of interest. Such methodsmay include radioimmunoassay (RIA) or enzyme linked immunoabsorbanceassay (ELISA), immunohistochemistry, immunofluorescent histochemistrywith or without confocal microscopy, Raman spectroscopy, X-rayautoradiography, X-ray radiography, luminescence spectrometry, reversedphase assays, homogeneous enzyme immunoassays, and related non-enzymatictechniques, Western blots, whole cell staining, immunoelectronmicroscopy, nucleic acid amplification, gene array, protein array, massspectrometry, patch clamp, 2-dimensional gel electrophoresis,differential display gel electrophoresis, microsphere-based multiplexprotein assays, label-free cellular assays and flow cytometry, etc. U.S.Pat. No. 4,568,649 describes ligand detection systems, which employscintillation counting. These techniques are particularly useful formodified protein parameters. Cell readouts for proteins and other celldeterminants can be obtained using fluorescent or otherwise taggedreporter molecules. Microscopy methods are useful for measuringparameters in a morphological context. Flow cytometry methods are usefulfor measuring intracellular parameters.

When using fluorescent labeled components in the methods andcompositions of the present invention, it will recognized that differenttypes of fluorescent monitoring systems, e.g., Cytometric measurementdevice systems, can be used to practice the invention. In someembodiments, flow cytometric systems are used or systems dedicated tohigh throughput screening, e.g. 96 well or greater microtiter plates,e.g., Lakowicz, J. R., Principles of Fluorescence Spectroscopy, NewYork: Plenum Press (1983); Herman, B., Resonance energy transfermicroscopy, in: Fluorescence Microscopy of Living Cells in Culture, PartB. Methods in Cell Biology, vol. 30, ed. Taylor, D. L. & Wang, Y. L.,San Diego: Academic Press (1989), pp. 219-243; Turro, N. J., ModernMolecular Photochemistry, Menlo Park: Benjamin/Cummings Publishing Col,Inc. (1978), pp. 296-361. Where the COBs/ESB complex is fluorescentlylabeled, suitable consideration of appropriate excitation sources may beinvestigated. Possible sources may include but are not limited to arclamp, xenon lamp, lasers, light emitting diodes or some combinationthereof. The appropriate excitation source is used in conjunction withan appropriate optical detection system, for example an invertedfluorescent microscope, an epi-fluorescent microscope or a confocalmicroscope. Preferably, a microscope is used that can allow fordetection with enough spatial resolution to determine the sequence ofthe spots on the COB/ESB complexes. If for example, the COB/ESBcomplexes are labeled with three different colors, Alexa 488, Cy3 andAlexa 647 (labeled 1, 2 and 3, respectively). Colors 1, 2 and 3 are eachacquired in different channels and the first and second registers, whichcan be seen as rows of spots, are shifted up by several pixels to beable to show each register individually. Examples of methods fordetection of multiple colors that can be used in the methods of theinvention are described in U.S. Pat. No. 7,473,767, U.S. patentpublication no. 2007/0166708, U.S. application Ser. No. 11/645,270, andPCT application no U.S. Ser. No. 06/049,274, incorporated by referenceherein in its entirety.

Fluorescence in a sample can be measured using a fluorimeter. Othermethods of detecting fluorescence may also be used, e.g., Quantum dotmethods (see, e.g., Goldman et al., J. Am. Chem. Soc. (2002)124:6378-82; Pathak et al. J. Am. Chem. Soc. (2001) 123:4103-4; andRemade et al., Proc. Natl. Sci. USA (2000) 18:553-8, each expresslyincorporated herein by reference) as well as confocal microscopy.

In some embodiments, a FACS cell sorter (e.g. a FACSVantage™, LSRII, orCanto Cell Sorter, Becton Dickinson Immunocytometry Systems, San Jose,Calif.) is used to sort and collect cells based on the presence orabsence of an COB/ESB complex. By imparting an electromagnetic charge todroplets containing the positive cells, the cells can be separated fromother cells. The positively selected cells can then be harvested insterile collection vessels. These cell-sorting procedures are describedin detail, for example, in the FACSVantage™. Training Manual, withparticular reference to sections 3-11 to 3-28 and 10-1 to 10-17, whichis hereby incorporated by reference in its entirety for the aboveinstruments.

In another embodiment, positive cells can be sorted using magneticseparation of cells based on the presence of a COB/ESB complex. In suchseparation techniques, cells to be positively selected are firstcontacted with a COB/ESB complex comprising retrievable particles (e.g.,magnetically responsive particles). The cell can then be physicallyseparated from non-positive or non-labeled cells, for example, using amagnetic field. When using magnetically responsive particles, thepositive or labeled cells can be retained in a container using amagnetic field while the negative cells are removed. These and similarseparation procedures are described, for example, in the BaxterImmunotherapy Isolex training manual which is hereby incorporated in itsentirety.

In some embodiments, one or more cells are contained in a well of a 96well plate or other commercially available multi-well plate. In analternate embodiment, the reaction mixture or cells are in a cytometricmeasurement device. Other multi-well plates useful in the presentinvention include, but are not limited to 384 well plates and 1536 wellplates. Still other vessels for containing the reaction mixture or cellsand useful in the present invention will be apparent to the skilledartisan.

In some embodiments, the abundance of a COB/ESB complex is measuredusing Inductively Coupled Plasma Mass Spectrometer (ICP-MS). A UBA thathas been labeled with a specific element binds to the COB/ESB complex.When the cell is introduced into the ICP, it is atomized and ionized.The elemental composition of the cell, including the COB/ESB complex, ismeasured. The presence and intensity of the signals corresponding to thelabels on the COB/ESB complex indicates the abundance of the COB/ESBcomplexes on that cell (Tanner et al. Spectrochimica Acta Part B: AtomicSpectroscopy, (2007), 62(3):188-195).

In some embodiments the ‘flow cytometer’ is a microfluidic device wherethe cell measurements, or some of the measurements of the cell'scontents, are carried out in channels devised to direct cells pastdetection devices in parallel sets of multiple channels. See U.S. Pat.Nos. 7,378,280; 7,294,503; 7,294,298; and 6,830,936.

In some embodiments the cells, or some portion of their contents, aresonically encapsulated within individual droplets of liquid andinterrogated with detection devices designed to measure each individualdroplet's characteristics and the materials within such droplets.

Flexible hardware and software allows instrument adaptability formultiple applications. The software program modules allow creation,modification, and running of methods. The system diagnostic modulesallow instrument alignment, correct connections, and motor operations.Customized tools, labware, and liquid, particle, cell and organismtransfer patterns allow different applications to be performed.Databases allow method and parameter storage. Robotic and computerinterfaces allow communication between instruments.

In some embodiments, the methods of the invention include the use ofliquid handling components. The liquid handling systems can includerobotic systems comprising any number of components. In addition, any orall of the steps outlined herein may be automated; thus, for example,the systems may be completely or partially automated.

As will be appreciated by those in the art, there are a wide variety ofcomponents which can be used, including, but not limited to, one or morerobotic arms; plate handlers for the positioning of microplates;automated lid or cap handlers to remove and replace lids for wells onnon-cross contamination plates; tip assemblies for sample distributionwith disposable tips; washable tip assemblies for sample distribution;96 well loading blocks; cooled reagent racks; microtiter plate pipettepositions (optionally cooled); stacking towers for plates and tips; andcomputer systems.

Fully robotic or microfluidic systems include automated liquid-,particle-, cell- and organism-handling including high throughputpipetting to perform all steps of screening applications. This includesliquid, particle, cell, and organism manipulations such as aspiration,dispensing, mixing, diluting, washing, accurate volumetric transfers;retrieving, and discarding of pipet tips; and repetitive pipetting ofidentical volumes for multiple deliveries from a single sampleaspiration. These manipulations are cross-contamination-free liquid,particle, cell, and organism transfers. This instrument performsautomated replication of microplate samples to filters, membranes,and/or daughter plates, high-density transfers, full-plate serialdilutions, and high capacity operation.

In some embodiments, chemically derivatized particles, plates,cartridges, tubes, magnetic particles, or other solid phase matrix withspecificity to the assay components are used. The binding surfaces ofmicroplates, tubes or any solid phase matrices include non-polarsurfaces, highly polar surfaces, modified dextran coating to promotecovalent binding, antibody coating, affinity media to bind fusionproteins or peptides, surface-fixed proteins such as recombinant proteinA or G, nucleotide resins or coatings, and other affinity matrix areuseful in this invention.

In some embodiments, platforms for multi-well plates, multi-tubes,holders, cartridges, minitubes, sonic levitation and encapsulation,deep-well plates, microfuge tubes, cryovials, square well plates,filters, chips, microchannel chips, microfluidics chips, optic fibers,beads, and other solid-phase matrices or platform with various volumesare accommodated on an upgradeable modular platform for additionalcapacity. This modular platform includes a variable speed orbitalshaker, and multi-position work decks for source samples, sample andreagent dilution, assay plates, sample and reagent reservoirs, pipettetips, and an active wash station. In some embodiments, the methods ofthe invention include the use of a plate reader.

In some embodiments, thermocycler and thermoregulating systems are usedfor stabilizing the temperature of heat exchangers such as controlledblocks or platforms to provide accurate temperature control ofincubating samples from 0° C. to 100° C.

In some embodiments, interchangeable pipet heads (single ormulti-channel) with single or multiple magnetic probes, affinity probes,or pipettors robotically manipulate the liquid, particles, cells, andorganisms. Multi-well or multi-tube magnetic separators or platformsmanipulate liquid, particles, cells, and organisms in single or multiplesample formats.

In some embodiments, the instrumentation will include a detector, whichcan be a wide variety of different detectors, depending on the labelsand assay. In some embodiments, useful detectors include a microscope(s)with multiple channels of fluorescence; plate readers to providefluorescent, ultraviolet and visible spectrophotometric detection withsingle and dual wavelength endpoint and kinetics capability,fluorescence resonance energy transfer (FRET), luminescence, quenching,two-photon excitation, and intensity redistribution; CCD cameras tocapture and transform data and images into quantifiable formats; and acomputer workstation.

In some embodiments, the robotic apparatus includes a central processingunit which communicates with a memory and a set of input/output devices(e.g., keyboard, mouse, monitor, printer, etc.) through a bus. Again, asoutlined below, this may be in addition to or in place of the CPU forthe multiplexing devices of the invention. The general interactionbetween a central processing unit, a memory, input/output devices, and abus is known in the art. Thus, a variety of different procedures,depending on the experiments to be run, are stored in the CPU memory.

These robotic fluid handling systems can utilize any number of differentreagents, including buffers, reagents, samples, washes, assay componentssuch as label probes, etc.

Applications for Target Molecule Detection

The compositions and methods of the invention can be used fordiagnostic, prognostic, therapeutic, patient stratification, drugdevelopment, treatment selection, and screening purposes. The presentinvention provides the advantage that many different target moleculescan be analyzed at one time from a single biomolecular sample using themethods of the invention. This allows, for example, for severaldiagnostic tests to be performed on one sample.

The composition and methods of the invention can be used in proteomics.The methods described herein will typically provide an answer rapidlywhich is very desirable for this application. The methods andcomposition described herein can be used in the process of findingbiomarkers that may be used for diagnostics or prognostics and asindicators of health and disease. The methods and composition describedherein can be used to screen for drugs, e.g., drug development,selection of treatment, determination of treatment efficacy and/oridentify targets for pharmaceutical development. The ability to testprotein expression on screening assays involving drugs is very importantbecause proteins are the final gene product in the body. In someembodiments, the methods and compositions described herein will measureboth protein and gene expression simultaneously which will provide themost information regarding the particular screening being performed.

The composition and methods of the invention can be used in geneexpression analysis. The methods described herein discriminate betweennucleotide sequences. The difference between the target nucleotidesequences can be, for example, a single nucleic acid base difference, anucleic acid deletion, a nucleic acid insertion, or rearrangement. Suchsequence differences involving more than one base can also be detected.In some embodiments, the UBAs, e.g., oligonucleotide probe, havesubstantially the same length so that they hybridize to targetnucleotide sequences at substantially similar hybridization conditions.As a result, the process of the present invention is able to detectinfectious diseases, genetic diseases, and cancer. It is also useful inenvironmental monitoring, forensics, and food science. Examples ofgenetic analyses that can be performed on nucleic acids include e-g.,SNP detection, STR detection. RNA expression analysis, promotermethylation, gene expression, virus detection, viral subtyping and drugresistance.

The present methods can be applied to the analysis of biomolecularsamples obtained or derived from a patient so as to determine whether adiseased cell type is present in the sample, the stage of the disease,the prognosis for the patient, the ability to the patient to respond toa particular treatment, or the best treatment for the patient. Thepresent methods can also be applied to identify biomarkers for aparticular disease.

In some embodiments, the methods described herein are used in thediagnosis of a condition. As used herein the term “diagnose” or“diagnosis” of a condition includes predicting or diagnosing thecondition, determining predisposition to the condition, monitoringtreatment of the condition, diagnosing a therapeutic response of thedisease, and prognosis of the condition, condition progression, andresponse to particular treatment of the condition. For example, a bloodsample can be assayed according to any of the methods described hereinto determine the presence and/or quantity of markers of a disease ormalignant cell type in the sample, thereby diagnosing or staging the adisease or a cancer.

In some embodiments, the methods and composition described herein areused for the diagnosis and prognosis of a condition.

Numerous immunologic, proliferative and malignant diseases and disordersare especially amenable to the methods described herein. Immunologicdiseases and disorders include allergic diseases and disorders,disorders of immune function, and autoimmune diseases and conditions.Allergic diseases and disorders include but are not limited to allergicrhinitis, allergic conjunctivitis, allergic asthma, atopic eczema,atopic dermatitis, and food allergy. Immunodeficiencies include but arenot limited to severe combined immunodeficiency (SCID),hypereosinophilic syndrome, chronic granulomatous disease, leukocyteadhesion deficiency I and II, hyper IgE syndrome, Chediak Higashi,neutrophilias, neutropenias, aplasias, Agammaglobulinemia, hyper-IgMsyndromes, DiGeorge/Velocardial-facial syndromes and Interferongamma-TH1 pathway defects. Autoimmune and immune dysregulation disordersinclude but are not limited to rheumatoid arthritis, diabetes, systemiclupus erythematosus, Graves' disease, Graves ophthalmopathy, Crohn'sdisease, multiple sclerosis, psoriasis, systemic sclerosis, goiter andstruma lymphomatosa (Hashimoto's thyroiditis, lymphadenoid goiter),alopecia aerata, autoimmune myocarditis, lichen sclerosis, autoimmuneuveitis, Addison's disease, atrophic gastritis, myasthenia gravis,idiopathic thrombocytopenic purpura, hemolytic anemia, primary biliarycirrhosis, Wegener's granulomatosis, polyarteritis nodosa, andinflammatory bowel disease, allograft rejection and tissue destructivefrom allergic reactions to infectious microorganisms or to environmentalantigens.

Proliferative diseases and disorders that may be evaluated by themethods of the invention include, but are not limited to,hemangiomatosis in newborns; secondary progressive multiple sclerosis;chronic progressive myelodegenerative disease; neurofibromatosis;ganglioneuromatosis; keloid formation; Paget's Disease of the bone;fibrocystic disease (e.g., of the breast or uterus); sarcoidosis;Peronies and Duputren's fibrosis, cirrhosis, atherosclerosis andvascular restenosis.

Malignant diseases and disorders that may be evaluated by the methods ofthe invention include both hematologic malignancies and solid tumors.

Hematologic malignancies are especially amenable to the methods of theinvention when the sample is a blood sample, because such malignanciesinvolve changes in blood-borne cells. Such malignancies includenon-Hodgkin's lymphoma, Hodgkin's lymphoma, non-B cell lymphomas, andother lymphomas, acute or chronic leukemias, polycythemias,thrombocythemias, multiple myeloma, myelodysplastic disorders,myeloproliferative disorders, myelofibroses, atypical immunelymphoproliferations and plasma cell disorders.

Plasma cell disorders that may be evaluated by the methods of theinvention include multiple myeloma, amyloidosis and Waldenstrom'smacroglobulinemia.

Example of solid tumors include, but are not limited to, colon cancer,breast cancer, lung cancer, prostate cancer, brain tumors, centralnervous system tumors, bladder tumors, melanomas, liver cancer,osteosarcoma and other bone cancers, testicular and ovarian carcinomas,head and neck tumors, and cervical neoplasms.

Genetic diseases can also be detected by the process of the presentinvention. This can be carried out by prenatal or post-natal screeningfor chromosomal and genetic aberrations or for genetic diseases.Examples of detectable genetic diseases include: 21 hydroxylasedeficiency, cystic fibrosis, Fragile X Syndrome, Turner Syndrome,Duchenne Muscular Dystrophy, Down Syndrome or other trisomies, heartdisease, single gene diseases, HLA typing, phenylketonuria, sickle cellanemia, Tay-Sachs Disease, thalassemia, Klinefelter Syndrome, HuntingtonDisease, autoimmune diseases, lipidosis, obesity defects, hemophilia,inborn errors of metabolism, and diabetes.

The methods described herein can be used to diagnose pathogeninfections, for example infections by intracellular bacteria andviruses, by determining the presence and/or quantity of markers ofbacterium or virus, respectively, in the sample.

A wide variety of infectious diseases can be detected by the process ofthe present invention. Typically, these are caused by bacterial, viral,parasite, and fungal infectious agents. The resistance of variousinfectious agents to drugs can also be determined using the presentinvention.

Bacterial infectious agents which can be detected by the presentinvention include Escherichia coli. Salmonella, Shigella, KLESBiella,Pseudomonas, Listeria monocytogenes, Mycobacterium tuberculosis,Mycobacterium aviumintracellulare, Yersinia, Francisella, Pasteurella,Brucella, Clostridia, Bordetella pertussis, Bacteroides, Staphylococcusaureus, Streptococcus pneumonia, B-Hemolytic strep., Corynebacteria,Legionella, Mycoplasma, Ureaplasma, Chlamydia, Neisseria gonorrhea,Neisseria meningitides, Hemophilus influenza, Enterococcus faecalis,Proteus vulgaris, Proteus mirabilis, Helicobacter pylori, Treponemapalladium, Borrelia burgdorferi, Borrelia recurrentis, Rickettsialpathogens, Nocardia, and Actinomycetes.

Fungal infectious agents which can be detected by the present inventioninclude Cryptococcus neoformans, Blastomyces dermatitidis, Histoplasmacapsulatum, Coccidioides immitis, Paracoccidioides brasiliensis, Candidaalbicans, Aspergillus fumigatus, Phycomycetes (Rhizopus), Sporothrixschenckii, Chromomycosis, and Maduromycosis.

Viral infectious agents which can be detected by the present inventioninclude human immunodeficiency virus, human T-cell lymphocytotrophicvirus, hepatitis viruses (e.g., Hepatitis B Virus and Hepatitis CVirus), Epstein-Barr Virus, cytomegalovirus, human papillomaviruses,orthomyxo viruses, paramyxo viruses, adenoviruses, corona viruses,rhabdo viruses, polio viruses, toga viruses, bunya viruses, arenaviruses, rubella viruses, and reo viruses.

Parasitic agents which can be detected by the present invention includePlasmodium falciparum, Plasmodium malaria, Plasmodium vivax, Plasmodiumovale, Onchoverva volvulus, Leishmania, Trypanosoma spp., Schistosomaspp., Entamoeba histolytica, Cryptosporidium, Giardia spp., Trichomonasspp., Balantidium coli, Wuchereria bancrofti, Toxoplasma spp.,Enterobius vermicularis, Ascaris lumbricoides, Trichuris trichiura,Dracunculus medinensis, Trematodes, Diphyllobothrium latum, Taenia spp.,Pneumocystis carinii, and Necator americanus.

The present invention is also useful for detection of drug resistance byinfectious agents. For example, vancomycin-resistant Enterococcusfaecium, methicillin-resistant Staphylococcus aureus,penicillin-resistant Streptococcus pneumoniae, multi-drug resistantMycobacterium tuberculosis, and AZT-resistant human immunodeficiencyvirus can all be identified with the present invention

Thus, the target molecules detected using the compositions and methodsof the invention can be either patient markers (such as a cancer marker)or markers of infection with a foreign agent, such as bacterial or viralmarkers.

Because of the quantitative nature of UBA/ESB/COBs, the compositions andmethods of the invention can be used to quantify target molecule whoseabundance is indicative of a biological state or disease condition, forexample, blood markers that are upregulated or downregulated as a resultof a disease state.

In some embodiments, the methods and compositions of the presentinvention can be used for cytokine detection. The low sensitivity of themethods described herein would be helpful for early detection ofcytokines, e.g., as biomarkers of a condition, diagnosis or prognosis ofa disease such as cancer, and the identification of subclinicalconditions.

Kits

The invention further provides kits comprising one or more components ofthe invention. The kits can comprise, for example, one or more UBAs, oneor more ESBs, and/or one or more APSs. The kits can be used for anypurpose apparent to those of skill in the art, including those describedabove.

In certain embodiments, the present invention also provides kits usefulfor the extension and selective immobilization of COBs, UBAs. ESBsand/or a combination thereof. The kits can comprise a substrate forimmobilization and one or more binding partners to facilitate extensionor immobilization of a COB, UBA, ESB and/or a combination thereof. Thebinding partners could, in certain embodiments, comprise a moiety usefulfor extension of the COB, UBA, ESB and/or a combination thereof, in anappropriate force. In certain embodiments, the binding partners couldfacilitate immobilization or selective immobilization of the COB, UBA,ESB and/or a combination thereof, to the surface. In furtherembodiments, the kits could comprise a device capable of extending theCOB, UBA, ESB and/or a combination thereof.

The kits can contain a population of COBs, APSs, UBAs. ESBs and/or acombination thereof as described herein.

The kits can contain pre-labeled APSs, or unlabeled APSs with one ormore components for labeling the APSs. Moreover, the ESBs and/or APSsprovided in a kit may or may not have UBAs pre-attached. In oneembodiment, the UBAs are provided in the kit unattached to the ESBsand/or APSs.

The kits can comprise other reagents such as linker oligos and bridgingoligos. In some embodiments, the kits can separate the UBAs intodifferent premixes.

The kits can include other reagents as well, for example, buffers forperforming hybridization reactions, linkers, restriction endonucleases,and DNA I ligases.

The kits also will include instructions for using the components of thekit, and/or for making and/or using the APSs, COBs, UBAs, and/or ESBs.

EXAMPLES Prophetic Example 1—Oligonucleotide Preparation

Oligonucleotides can be synthesized according to standard techniquesknown in the art. For instance, oligonucleotides can be synthesized on a394A DNA Synthesizer (Applied Biosystems Division of Perkin-Elmer Corp.,Foster City, Calif.).

The oligonucleotides are purified by ethanol precipitation afterovernight deprotection at 55° C. The primer-specific portions of theoligonucleotides used for PCR amplification are purified bypolyacrylamide gel electrophoresis on 10% acrylamide/7 M urea gels.Oligonucleotides are visualized after electrophoresis by UV shadowingagainst a lightening screen and excised from the gel (Applied BiosystemsInc., 1992). They are then eluted overnight at 64° C. in TNE (i.e.Tris-sodium EDTA) buffer (100 mM Tris/HCl pH 8.0 containing 500 mM NaCland 5 mM EDTA) and recovered from the eluate using Sep Pak cartridges(Millipore Corp, Milford, Mass.) following the manufacturer'sinstructions.

Oligonucleotides are resuspended in 100 μl TE (i.e. 10 mM Tri-HCl pH 8.0containing 1 mM EDTA). Typical concentrations of these originaloligonucleotide solutions are about 1 μg/μl or approximately 74 μm/μl.

As a prerequisite for ligation reactions, the oligonucleotides arephosphorylated with T4 polynucleotide kinase at the 5′-end. Aliquots ofthe oligonucleotides equivalent to 200 pm are combined with 10 μl of 10×kinase buffer (500 mM Tris/HCl pH 8.0, 100 mM MgCl₂), 10 μl of 10 mMATP, 20 U T4 kinase, and sufficient water-ME to give a final volume of100 μl. Phosphorylation is carried out at 37° C. for 30 min followed byincubation for 10 min at 85° C. to inactivate the T4 enzyme.

The solutions of the oligonucleotides are adjusted to convenientconcentrations. The kinased oligonucleotide solution is diluted fourfoldin water to yield a concentration of 1000 fm/μl. A solution of theoligonucleotides is made by combining volumes of the oligonucleotidesequivalent to 200 pm with sufficient water to give a final volume of 400μl. This created a solution 1000 fm/μl in each of the oligonucleotides.Aliquots (20 μl) of the kinased and unkinased oligonucleotides arefrozen for subsequent use.

General Method for Oligonucleotide Synthesis and Purification for ClickChemistry

Oligonucleotides are synthesized as described in El-Sagheer et al.(PNAS, 108:28, 11338-11343, 2011). Briefly, standard DNAphosphoramidites, solid supports and additional reagents are purchasedfrom Link Technologies and Applied Biosystems. Oligonucleotides aresynthesized on an Applied Biosystems 394 automated DNA/RNA synthesizerusing a standard 0.2 or 1.0 μmole phosphoramidite cycle ofacid-catalyzed detritylation, coupling, capping, and iodine oxidation.All β-cyanoethyl phosphoramidite monomers are dissolved in anhydrousacetonitrile to a concentration of 0.1 M immediately prior to use. Thecoupling time for normal A, G, C, and T monomers is 35 see, whereas thecoupling time for the reverse amidites is 180 sec. Alkynephosphoramidite monomer (2c in FIG. 2 , El-Sagheer et al., PNAS, 108:28,11338-11343, 2011) and other non-standard monomers are coupled for 360sec. Cleavage of oligonucleotides from the solid support anddeprotection is achieved by exposure to concentrated aqueous ammoniasolution for 60 min at room temperature followed by heating in a sealedtube for 5 hr at 55° C. The oligonucleotides are purified byreversed-phase HPLC on a Gilson system using an XBridge™ BEH300 Prep C1810 μM 10×250 mm column (Waters) with a gradient of acetonitrile inammonium acetate (0% to 50% buffer B over 30 min, flow rate 4 mL/min),buffer A: 0.1 M ammonium acetate, pH 7.0, buffer B: 0.1 M ammoniumacetate, pH 7.0, with 50% acetonitrile. Elution is monitored by UVabsorption at 305 or 295 nm. After HPLC purification, oligonucleotidesare desalted using NAP-10 columns and analyzed by gel electrophoresis.

i) Synthesis of 3′-alkyne Oligonucleotides

Synthesis of 3′-alkyne oligonucleotides is performed as described inEl-Sagheer et al. (PNAS, 108:28, 11338-11343, 2011). Briefly, 3′-Alkyneoligonucleotides are synthesized using the 3′-propargylthymidinephosphoramidite monomer 2c and assembling the required sequence in the5′ to 3′-direction using the3′-O-(4,4′-dimethoxytrityl)deoxyribonucleoside-5′-phosphor-amidites ofA, G, C and T (reverse phosphoramidites, Link Technologies) or by theattachment of5′-O-(4,4′-dimethoxytrityl)-3′-O-propargyl-5-methyl-deoxycytidine tosolid support (33 μmol/g loading, AM polystyrene, Applied Biosystems)according to El-Sagheer et al. (Proc. Natl. Acad. Sci. U.S.A.107(35):15329-15334). The resin is packed into a twist column (GlenResearch), then used to assemble the required sequence in the 3′- to5′-direction by standard phosphoramidite oligonucleotide synthesis. Theoligonucleotides are then cleaved, deprotected and purified as describedabove.

ii) Synthesis of 5′-azide Oligonucleotides

Synthesis of 5′-azide oligonucleotides is performed as described inEl-Sagheer et al. (PNAS, 108:28, 11338-11343, 2011). Briefly,oligonucleotides are assembled on the 0.2 or 1.0 μmol scale (trityl-off)as described in the general method (above) with normal 5′-HO-dC,5′-HO-dT (or with 5′-iodo-dT using the commercially available 5′-iodo dTmonomer from Glen Research). To convert the 5′-hydroxyl group to5′-iodo, the protected oligomers attached to the synthesis column aretreated with a 0.5 M solution of methyltriphenoxyphosphonium iodide inDMF (1.0 mL), which is periodically passed through the column via two 1mL syringes over 15 min at room temperature. The column is then washedseveral times with dry DMF. To convert the 5′-iodo (dT or dC) to5′-azido (dT or dC), sodium azide (50 mg) is suspended in dry DMF (1mL), heated for 10 min at 70° C. then cooled down and the supernatanttaken up into a 1 mL syringe, passed back and forth through the columnthen left at room temperature overnight (or for 5 hr at 55° C.). Thecolumn is then washed with DMF and acetonitrile and dried by the passageof a stream of argon gas. The resultant 5′-azide oligonucleotide iscleaved from the solid support, deprotected and purified as describedabove.

iii) Synthesis of 3′-alkyne-5′-azide Oligonucleotides

Synthesis of 3′-alkyne-5′-azide oligonucleotides is performed asdescribed in El-Sagheer et al. (PNAS, 108:28, 11338-11343, 2011).Briefly,5′-O-(4,4′-Dimethoxytrityl)-3′-O-propargyl-5-methyldeoxycytidine onpolystyrene solid support is packed into a twist column (Glen Research)and used to assemble the required sequence in the 3′- to 5′-direction(standard phosphoramidite oligonucleotide synthesis) with 5′-iodo dT,5′-HO-dT or 5′-HO-dC at the 5′-end. The 5′-hydroxyl or iodo groups arethen converted to azide using the conditions described above for thesynthesis of the 5′-azide oligonucleotides.

Prophetic Example 2. Click Chemistry Ligation

Oligonucleotide APSs are annealed to a template and kept overnight at 4°C. A solution of Cu^(I) click catalyst is prepared fromtris-hydroxypropyltriazole ligand as described in Chan et al. (Chan T R,Hilgraf R, Sharpless K B, & Fokin V V (2004) Polytriazoles ascopper(I)-stabilizing ligands in catalysis. Org. Lett. 6(17):2853-2855;2.8 μmol in 0.2 M NaCl, 38.0 μL), sodium ascorbate (4.0 μmol in 0.2 MNaCl, 8.0 μL) and CuSO4.5H2O (0.4 μmol in 0.2 M NaCl, 4.0 μL). Thissolution is added to the annealed oligonucleotides and the reactionmixture is kept at 0° C. for 1 hr, then at room temperature for afurther 1 hr. Reagents are removed using a NAP-25 gel-filtration column.

Prophetic Example 3. Split-Pool Synthesis of COBs on Beads

In this Example COBs are synthesized attached to beads. 4 differentmethods are used for the assembly of APSs into COBs:

Patchwork COB (FIG. 6 )

Aminomethyl macroporous polystyrene (MPPS) beads are labeled with tendifferent CL oligonucleotides, each with an optional first amplificationprimer complementary region, one of 10 different ESB sequences and acommon annealing region. Six rounds of split pool synthesis areperformed. In each round, beads are split into 20 different containers.A different oligonucleotide APS is added to each container, totaling 20different APSs. Each APS in a given round further comprises a uniquesubcode sequence that is different from the rest of the APSs in thatround.

In the first round, each APS comprises an annealing region 1 that iscomplementary to the annealing region of the CL oligonucleotide on oneend and an annealing region 2 on the other end. Upon addition, theoligonucleotide APS hybridizes to the CL oligonucleotide along thecomplementary annealing region 1. The annealing region 2 remains singlestranded and available to hybridization with an APS added in thesubsequent round. In subsequent rounds, each APS comprises an annealingregion complementary to the available annealing region of the APS fromthe previous round on one end and an additional annealing region on theother end. The added APS hybridizes to the APS added in the previousround along the complementary annealing region.

The last subunit optionally comprises a second amplification primercomplimentary region for hybridization of PCR or sequencing primers.

A CL, or one or more APSs further comprise a random tag region, whichacts as a molecular counter as described supra, allowing for subsequentnormalization of the detected COBs.

Upon the addition of an APS in each round, the beads are pooled anddivided into new 20 pools initiating the subsequent round. A new set of20 APSs are added in each round with a pair of round specific annealingregion as described above. After the addition of 6 APSs, the hybridizedAPSs on the beads are patched together using a polymerase/ligase. TheCOBs are optionally PCR amplified for sequencing using primers targetingthe amplification primer complementary regions on the CL and the lastAPS subunit

Stitch COB Using Specific Annealing of Primers (FIG. 7 )

Aminomethyl macroporous polystyrene (MPPS) beads are labeled with tendifferent CL oligonucleotides, each with an optional first amplificationprimer complementary region, a one of 10 different ESB sequences and acommon annealing region. Six rounds of split pool synthesis areperformed. In each round, beads are split into 20 different containers.A different oligonucleotide APS is added to each container, totaling 20different APSs. Each APS in a given round further comprises a uniquesubcode sequence that is different from the rest of the APSs in thatround.

An annealing primer is also added. In the first round, the annealingprimer has a complementary region to the CL oligonucleotide and acomplementary region to the APS. The annealing primer hybridizes toboth, stitching them together. In subsequent rounds, the annealingprimer has a complementary region to the APS added during the previousround and a complementary region to the APS being added in the currentround. Similarly, the annealing primer hybridizes to APSs fromsubsequent rounds stitching them together. The complementary regions ofthe annealing primer are specific to each round allowing efficienthybridization of subunits only from the previous and current rounds.Accordingly, the annealing primer does not hybridize to subunits ofearlier rounds, which would not have complementary regions to theannealing primer of a current round, thus blocking the further synthesisof COBs missing subunits of particular rounds.

The last subunit optionally comprises a second amplification primercomplimentary region for hybridization of PCR or sequencing primers.

A CL, or one or more APSs further comprise a random tag region, whichacts as a molecular counter as described supra, allowing for subsequentnormalization of the detected COBs.

Upon the addition of an APS and an annealing primer in each round, thebeads are pooled and divided into new 20 pools initiating the subsequentround. A new set of 20 APSs are added in each round with a pair of roundspecific annealing region as described above. After the addition of 6APSs, the hybridized APSs on the beads are permanently stitched togetherusing a polymerase/ligase or using Click chemistry as described inExample 2. The COBs are optionally PCR amplified for sequencing usingprimers targeting the amplification primer complementary regions on theCL and the last APS subunit.

Stitch COB Using Annealing of Primers with Common Complementary Regions(FIG. 8 )

Aminomethyl macroporous polystyrene (MPPS) beads are labeled with tendifferent CL oligonucleotides, each with an optional first amplificationprimer complementary region, a one of 10 different ESB sequences and acommon annealing region. Six rounds of split pool synthesis areperformed. In each round, beads are split into 20 different containers.A different oligonucleotide APS is added to each container, totaling 20different APSs. Each APS in a given round further comprises a uniquesubcode sequence that is different from the rest of the APSs in thatround.

An annealing primer is also added. In the first round, the annealingprimer has a first complementary region to the CL oligonucleotide and asecond complementary region to the APS being added in the current round.The annealing primer hybridizes to both, stitching them together. Insubsequent rounds, the annealing primer has a first complementary regionto the APS added during the previous round and a second complementaryregion to the APS being added in the current round. Similarly, theannealing primer hybridizes to APSs from subsequent rounds stitchingthem together. Of the two complementary regions of the annealing primer,the first complementary regions are specific to each round allowingefficient hybridization to subunits only from the previous round.Accordingly, the annealing primer does not hybridize to subunits ofearlier rounds, which would not have complementary regions to theannealing primer of a current round, thus blocking the further synthesisof COBs missing subunits of particular rounds.

The last subunit optionally comprises a second amplification primercomplimentary region for hybridization of PCR or sequencing primers.

A CL, or one or more APSs further comprise a random tag region, whichacts as a molecular counter as described supra, allowing for subsequentnormalization of the detected COBs.

Upon the addition of an APS and an annealing primer in each round, thebeads are pooled and divided into new 20 pools initiating the subsequentround. A new set of 20 APSs are added in each round with a pair of roundspecific annealing region as described above. After the addition of 6APSs, the hybridized APSs on the beads are permanently stitched togetherusing a polymerase/ligase or using Click chemistry as described inExample 2. The COBs are optionally PCR amplified for sequencing usingprimers targeting the amplification primer complementary regions on theCL and the last APS subunit.

Loop COB (FIG. 9 )

Aminomethyl macroporous polystyrene (MPPS) beads are labeled with tendifferent CL oligonucleotides, each with an optional first amplificationprimer complementary region, one of 10 different ESB sequences, sixpairs of APS-specific loop annealing regions and an optional secondamplification primer complementary region. Six rounds of split poolsynthesis are performed. In each round, beads are split into 20different containers. A different oligonucleotide APS is added to eachcontainer, totaling 20 different APSs. Each APS in a given round furthercomprises a unique subcode sequence that is different from the rest ofthe APSs in that round.

The APSs are designed to hybridize to the CL in a loop geometry,hybridizing on each end to the CL along the loop annealing regionsspecific to the round. The hybridization populates the APSs along theCL, which are then linked together. The APSs are designed such that theydo not efficiently hybridize to the CL along the loop annealing regionsspecific to other rounds. Consequently, if an APS from a particularround is missing, the APSs may not be linked together successfully,depending on the linking process. Alternatively, a COB is synthesizedwith a missing APS, the location of which is flanked by a pair of loopannealing regions. The resulting COB can then be analyzed accordinglyand can either be discarded or the retrieved information can bealternatively processed.

A CL, or one or more APSs further comprise a random tag region, whichacts as a molecular counter as described supra, allowing for subsequentnormalization of the detected COBs.

Upon the addition of an APS and an annealing primer in each round, thebeads are pooled and divided into new 20 pools initiating the subsequentround. A new set of 20 APSs are added in each round with a pair of roundspecific annealing region as described above. After the addition of 6APSs, the hybridized APSs on the beads are permanently stitched togetherusing a polymerase/ligase or using Click chemistry as described inExample 1. The COBs are optionally PCR amplified for sequencing usingprimers targeting the amplification primer complementary regions on theCL.

Polymerase Free COB-ESB Linkage (FIG. 10 )

Aminomethyl macroporous polystyrene (MPPS) beads are labeled with tendifferent CL oligonuclotides, each with a pair of loop annealing regionspecific for one of the 10 different loop ESB sequences, and six pairsof APS-specific loop annealing regions. All 10 loop ESB sequences areadded to anneal to the loop ESB specific portion of the CL in a loopgeometry. Loop ESB sequences are designed to minimize non-specificannealing to the remainder of the loop ESB specific regions of the CLs.Loop ESB sequences comprise an optional first amplification primercomplementary region, an ESB sequence, and a pair of annealing regionssufficiently complementary to the loop ESB-specific loop annealingregions in the CL. Six rounds of split pool synthesis are performed. Ineach round, beads are split into 20 different containers. A differentoligonucleotide APS is added to each container, totaling 20 differentAPSs. Each APS in a given round further comprises a unique subcodesequence that is different from the rest of the APSs in that round. TheAPSs in the final round optionally further comprise a secondamplification primer complementary region.

The APSs are designed to hybridize to the CL in a loop geometry,hybridizing on each end to the CL along the loop annealing regionsspecific to the round. The hybridization populates the APSs along theCL, which are then linked together. The APSs are designed such that theydo not efficiently hybridize to the CL along the loop annealing regionsspecific to other rounds. Consequently, if an APS from a particularround is missing, the APSs may not be linked together successfully,depending on the linking process. Alternatively, a COB is synthesizedwith a missing APS, the location of which is flanked by a pair of loopannealing regions. The resulting COB can then be analyzed accordinglyand can either be discarded or the retrieved information can bealternatively processed.

A CL, or one or more APSs further comprise a random tag region, whichacts as a molecular counter as described supra, allowing for subsequentnormalization of the detected COBs.

Upon the addition of an APS and an annealing primer in each round, thebeads are pooled and divided into new 20 pools initiating the subsequentround. A new set of 20 APSs are added in each round with a pair of roundspecific annealing region as described above. After the addition of 6APSs, the hybridized APSs on the beads are permanently stitched togetherusing a using Click chemistry as described in Example 2. The COBs areoptionally PCR amplified for sequencing using primers targeting theamplification primer complementary regions on the CL and the last APSsubunit.

Prophetic Example 4. Detection by Nucleic Acid Sequencing

The assembled ESB-linked COBs resulting from any of the methods inExample 3 are sequenced by Illumina's HiSeq 2000 machine. The resultingsequences comprise at least one of 10 different ESB sequences, a randomtag region, and a combination of 6 subcodes originating from APSs addedto that particular bead during the 6 rounds of split pool synthesis.

Prophetic Example 5. Detection by Peptide Sequencing (FIG. 11)

ESB-linked COBs are synthesized using any of the methods in Example 3.The resulting sequences comprise a T7 promoter an SP6 start site, astart codon, an ESB, a COB and optionally a region encoding a His(6) tag(FIG. 11 ). The T7 promoter and SP6 start site can be incorporated intothe sequence linked to the ESB, using the same method that is used toincorporated the ESB. Alternatively, these sequences can be incorporatedwithin the last APS. Optionally, a His(6) tag encoding region can beincorporated linked to the final APS or to the ESB.

The assembled ESB-linked COBs are transcribed and translated intopeptide sequences using the Expressway™ Maxi Cell-Free E. coliExpression System (Invitrogen). The peptide sequences are isolated usingaffinity chromatography and/or HPLC prior to being sequenced using atandem mass spectrometer.

Prophetic Example 6. Split-Pool Synthesis of COBs on Cell Surfaces

Cell surface receptors on leukocyte cell lines (HL60, JY and U937) aredetected and quantified using split-pool synthesis of COBs on cellsurfaces. Using Antibody-Oligonucleotide All-in-One Conjugation Kit(Solulink), antibodies against CD1, CD3, CD8 and CD4 are conjugated withamine modified CL oligonucleotides described in Example 3. Thesingly-labeled antibodies are isolated using affinity chromatographyusing complementary oligonucleotides targeting a sequence in CLoligonucleotides and the number of labels on each antibody is verifiedusing mass spectrometry. A cell suspension of 10⁷ cells are incubatedwith the combination of the antibodies under suitable conditionsfollowed by 6 rounds of split-pool synthesis. The resulting ESB-linkedCOBs are detected as described in Example 3 or Example 4. The detectedsignals related to COB-linked ESBs are quantified for each COBcombination. Co-expression of each of the CD1, CD3, CD8, and CD4antigens on the cells are plotted pairwise. Principle component analysisis used to identify the strongest correlations in expression profiles.

Prophetic Example 7. Split-Pool Synthesis of COBs in Cells

Methanol is cooled to −20° C. A cell culture comprising 10⁷ HeLa cellsis grown using suitable tissue culture conditions known in the art. Thegrowth medium is removed by aspiration. The cells are immediately fixedand permeabilized by adding 50 mL cold methanol. The cells are allowedto incubate at ambient temperature for 10 minutes with gentle shaking.Methanol is carefully removed by aspiration. The cells are rinsed with100 mL of 1×PBS, three times.

The cells are blocked with 150 ml of 0.1% Casein solution in 0.2% PBSfor 1.5 hrs at room temperature by gentle shaking. Rabbit anti-cleavedcaspase-3, rabbit anti phos-p38, rabbit anti-phos-ERK2, mouse anti-ERK2,and mouse anti-β-tubulin (clone AA2) are CL-conjugated as described inExample 5. Cells are incubated with CL-conjugated antibodies overnightat 4° C., gently shaking. The cells are washed 5 times with 1×PBS+0.1%Tween-20 for 5 minutes at room temperature, followed by 6 rounds ofsplit-pool synthesis.

The resulting ESB-linked COBs are detected as described in Example 3 orExample 4. The detected signals related to COB-linked ESBs arequantified for each COB combination. Co-expression of each of thePhospho-p53, ERK1 in the cells are plotted pairwise. Principle componentanalysis is used to identify the strongest correlations in expressionprofiles.

While preferred embodiments of the present invention have been shown anddescribed herein, it will be obvious to those skilled in the art thatsuch embodiments are provided by way of example only. Numerousvariations, changes, and substitutions will now occur to those skilledin the art without departing from the invention. It should be understoodthat various alternatives to the embodiments of the invention describedherein may be employed in practicing the invention. It is intended thatthe following claims define the scope of the invention and that methodsand structures within the scope of these claims and their equivalents becovered thereby.

What is claimed is:
 1. A method comprising: (a) binding an agent to atarget molecule in a population of cells in a first reaction volume,wherein the agent comprises a target-specific nucleic acid barcode thatidentifies a corresponding target molecule; (b) separating the cellsinto a plurality of second reaction volumes, wherein at least some ofthe second reaction volumes receive a single cell from the population ofcells; and (c) adding a cell-specific nucleic acid barcode or complementthereof to the target-specific nucleic acid barcode or complementthereof in the second reaction volumes.
 2. The method of claim 1,wherein the method further comprises: (d) pooling a plurality of thesecond reaction volumes after step (c).
 3. The method of claim 2,wherein the method further comprises: (e) sequencing the product of step(c) after pooling.
 4. The method of claim 1, wherein the cells of (a)are fixed and/or permeabilized.
 5. The method of claim 1, wherein thecells are lysed between (b) and (c).
 6. The method of claim 1, whereinthe adding of (c) is done via hybridization, ligation, primer extension,or primer extension followed by ligation.
 7. The method of claim 1,wherein the second reaction volumes of (b) are droplets, microdroplets,wells, microwells, microbubbles, or enclosures in a microfluidicsdevice.
 8. The method of claim 1, wherein (c) is done by: combining atleast some of the second reaction volumes with a cell-specific nucleicacid barcode, wherein the second reaction volumes receive differentcell-specific nucleic acid barcodes; and incubating the second reactionvolumes under conditions sufficient to link the cell-specific nucleicacid barcode or complement thereof to the target-specific nucleic acidbarcode or complement thereof.
 9. The method of claim 8, wherein anucleic acid comprising the cell-specific nucleic acid barcode or anucleic acid comprising the target-specific nucleic acid barcode furthercomprises a random sequence.
 10. The method of claim 1, wherein thetarget molecule is a protein.
 11. The method of claim 1, wherein thetarget molecule is a nucleic acid.
 12. The method of claim 11, whereinthe target molecule is RNA or complementary DNA (cDNA).
 13. The methodof claim 1, wherein the target molecule is intracellular.
 14. The methodof claim 1, wherein the target molecule is on the surface of the cells.15. The method of claim 1, wherein the agent is anantibody-oligonucleotide conjugate.
 16. The method of claim 1, whereinthe agent is an oligonucleotide, an oligonucleotide probe, a primer oran aptamer.
 17. The method of claim 1, wherein: step (a) comprisesbinding a plurality of agents to a plurality of target molecules in thepopulation of cells, wherein each agent comprises a target-specificnucleic acid barcode that identifies the target molecule to which theagent binds, and step (c) comprises adding a cell-specific nucleic acidbarcode or complement thereof to the target-specific nucleic acidbarcodes or complements thereof in the second reaction volumes.
 18. Themethod of claim 1, wherein the cell-specific nucleic acid barcode orcomplement thereof and the target-specific nucleic acid barcode orcomplement thereof are added together on a bead.
 19. The method of claim1, wherein the cell-specific nucleic acid barcode comprises a series ofmonomeric subunits that forms a code that is associated with a specificcell.
 20. The method of claim 1, wherein the population of cells of (a)is contained in a well of a multi-well plate.
 21. The method of claim20, wherein the method is performed on a plurality of populations ofcells each contained in a well of a microtiter plate.